Sometimes if you are thinking and designing as you go you can end up with bad geometry, because you've added a bit here and chopped a bit off there and scaled that bit....you need to stop and cleanup a bit before you get too far ahead of yourself. So find the correct bits of your shape and use those to redraw a new component.
In other words, take the profile and the circles and their positions from your model as your starting point and make a new one correctly.
That's why it was so fast for me, I just saw four elements and put them together. You had to think up those elements to begin with.
As Gilles says, trying to fix stuff is often a waste of time when the parts can be quickly redrawn.
However, there is nothing wrong with "sketching" in sketchup, but knowing when to consolidate a piece is the trick, and very quickly you will start to find that you are "sketching" correctly and rarely have to go back and rebuild.
