I have made a first attempt. In fact I was looking for a way of doing it with a script or something similar, but I see I have to do it manually. Anyway thanks Alan.
I have to go out for three days, so I won't be able to respond you untill thursday. If you have another way to fix the problem, let me know 
I would like to do it using free software, like gimp (if possible). I have searched in Google for a solution, but I had no luck.
This is the effect:
I am not good with gimp or similar software, but I have to make a good stone texture and I know that is very important for the finished model.
Thanks.
The link of Rome is fantastic.
This is going to be interesting for you, Gaieus knows about it:
Sorry, in spanish. But enter and see it:
http://www.balawat.com/foroseg/pgfovir.htm (click on the numbers)
http://www.balawat.com/archcrque/paerea.htm
http://www.balawat.com/molino/pmolino.htm
http://www.balawat.com/calpe/pvicus2.htm
This is at 8 km from where I live:
Sorry, I didn't read your location 
If you need some translations from spanish let me know
I am sorry. As I am spanish I understand more than you, but there are a lot of things I don't.
Anyway download some of their models, they are well done and are very interesting, and fast.
I have created this thread to let you putting the interesting links you found on the net.
I want to share this link with you:
http://sketchreconstuctionarchitecture.blogspot.com/
This guy is making a model of the palace of Cnossos, you must see their models:
http://sketchup.google.com/3dwarehouse/search?uq=14704722087802546842
I hope somebody brings me a good place with textures of roman walls...
You need a rss... I use Google Reader to read blogs.
Anyway is a fantastic idea
@unknownuser said:
Also, your arcs need more segments.
Yes, I saw it looking at that render. I told you that is half done and full of mistakes... 
I know it, is half done.
And to be honest, now that nobody is reading us , I like more the work of "building" than texturing.
It's said that some people is going to give me textures of the walls (limestone and sandstone). Bump maps of it may be very hard to do.
Anyway I am looking for good textures of roman paintings, for the basilica, if someone can provide me I would thank him a lot.
Thread related (sketchup gallery):
I will post my renders of the roman theatre here. It has a lot of mistakes, and is half done, anyway I put it here if you are interested
This render is one of the two stairs in the east basilica. At right (you see it a little) there is a door to enter in the Basilica, at left (you don't see it) there is another door to the Aditus. The door in the middle of the stairs leads you to the tribunal, and at the top, you see a door in a room to communicate with the inma and media cavea. That room gets light from the big window of the Frons Scaenae".
Made with Kerkythea
I am catholic, but all the spanish have jew ancestors and I am proud of that (unfortunately almost all of them were forced to conversion, you know, the spanish inquisition 
). in Ciudad Real there were a lot of them, my city today is horrible with modern flats and buildings, but in the medieval period had one of the biggest jew colonies of Spain. It appears in a book of Noah Gordon.
In Toledo there are two synagogues, I have been in one of them, "Santa Maria la Blanca", white and elegant. It is very beautifoul.
But I believe that your wife was in the another one because is the most famous, the one I have never been, the "Sinagoga del Tránsito".
http://www.museosefardi.net/pagina4.html
http://www.flickr.com/search/?q=sinagoga%20tr%C3%A1nsito&w=all
If you want more inspiration:
http://inicia.es/de/conocer/Ciudades/Ciudad_Real/puerta2.JPG
The door (now in a Museum) of the medieval Synagogue of Ciudad Real (Spain). It's the only thing of that building we have
To be honest when I saw the doors and windows of your building inmediately come to my mind this door of Ciudad Real.
My situation is like yours...
¿Is it a real model like Liebherr? I saw one in 3D Warehouse. Good work, I hope to see it finished
Just a fast link of a image:
http://i30.tinypic.com/wqv7uu.jpg
It's a "Beta" of the full model in Google Earth. It's made in a fast way, there is a lot of work to do yet.
Gaieus: In fact, I visited le "Maison Carrée" 10 years ago
And there are rests of half columns "enclosing" the entrance in the Basilicae.
(Bottom left).
The roman theatre of cartagena was very well preserved but very "crushed". As you see in the photo you can imagine that no remnants of paintings have been found. But I see that there is a "fog" of secrecy and it will last untill the new Moneo's Museum opens in 1 or 2 months. Perhaps we may know something about it in the future.
Well, there are some occult walls, so you can't see the half column perfectly.
And I have to fix the base of the columns, is half done.
Gaieus, the problem is fixed.
And probably, the people won't see the work I have done, but I have enjoyed a lot. I have designed a possible distribution of the floors and stairs. Well, I haven't made the stairs (the empty rooms without floor at the right), as it is a lot of work. But at this moment I have a good guide to put the windows. And I have explained my self how the basilicae worked.
Anyway, I think that the room at the ground floor may have paintings. If you give me your opinion, It would be very usefull for me.
You don't understand me because I insist that my english is limited, sorry for that.
I will make a thinner wall to fix it, thanks for your help (It is going to give me a headache, as I have to make a new "half column component", I believe)
As I am too perfectionist, I am studying now the volumes inside the basilica to figure how it was, just with the few ruins we have. And I believe that I have an idea.
I don't know if the Basilica, inside it, had naked stone or there was any kind of paintings. I am thinking in the future, when I apply textures to it.
A New theory for a secondary use of the Frons Scaenae in Roman Theatres has been developed by Dr. Moebius Co&Jones:
(it's a joke for the spanish forums that perhaps you are not going to understand, the buildings sourrunding the roman theatre have a lot of this "esthetic" element and it's my idea of fighting against this "contrast" 
)
And I began the basilicae. To make work the columns in its proper way, I had to stretch part of the wall. It's a sollution I seen in Medina Azahara, (an arabian palace in Spain), but I don't know if Romans did it. Perhaps I should build walls thinner. Anyway is a part of the theatre with few elements known. Even the Ionic style is not known, I chose it because I had a ionic capital without use. The half columns may be wrong... I don't know.
I need orientation of an archeologist about that, as the people in the spanish forums have no idea (Gaieus... )
Your script will be fantastic. I haven't read all the thread and I don't know if anyone has mentioned it before, but... Is there any chance in the future of a "Combine and rough" script? It would be a solution to upload in 3D Warehouse some complex models (there is a limit in file size), to upload a low resolution model.
(I have looked for something like that, but I didn't have luck).
