Wow! Thank you so much d12dozr for taking your time making that tutorial for me! You solved all my problems! The ring is finally done. I made it a bit different than people here suggested because I was afraid that splitting the ring and mending it on the middle of the decoration would not only result in two mendings, but would also probably prove more difficult. I made the arc, but I made the line for it 1 mm and the radius the size of my rings diameter, which resulted in a circle with a 1 mm broken line. I then bent my shape around it and mended the small crack in the ring with curviloft. I smoothed the lines left from curviloft, and now the only thing that is tells of the mended part is a small shadow that I can't remove.
What I would finally like is for someone to have a look at the finnished ring and see if the model is broken in some way that I can't detect. I only notice the shadow, but I can't be sure that I realise the implications of it. After I get the approval here my intention is to head to Shapeaway and print it out in silver, and if the model is broken the printing might fail.
I will also post the model on Shapeway's forum asking if the model follows the guidelines for silver printing, so that's not my concern at this moment.
Attached is my .skp for the finnished ring, and I promise I will also post a picture of the ring when it finally arrives