thanks for the picture. It helps.
Both of the lights need to be positioned over the basking area. Right now, the UVB bulb is so far away from the basking turtle it's probably not reaching him to any effective degree. It's going to be hard to get the UVB bulb close enough with the heat bulb fixture as it is because the heat bulb fixture takes up so much room.
Have you checked out photos of other setups in the habitat gallery section? It will give you some ideas about types of fixtures and the placement of bulbs.
http://www.redearslider.com/habitat_gallery.html
Here's the info on basking and lighting:
http://www.redearslider.com/index_lighting_basking.html
Why don't you take a look at the photos and then if you have questions, get back to us. I think if you simply replace the UVB and heat bulb, your turtle is going to have shell problems because he's not really getting the UVB he needs when he's basking.
Lighting is one of the trickiest parts of the setup. Once you get if all down, though, it's not so bad.