Ps3 – the black cloud that appears behind some of the characters

A fix for this isn't mentioned in the 3.60 release notes or the 3.56 release notes. I would recommend you perform the update. At worse, it doesn't fix the issue, and you're in the same state. (It might have actually been the 3.50 update that caused the issue. Sony added support for 3D games/movies in that release.)

I've never used a PS3 repair service, so can't recommend one. Have you tried Sony's service page? It takes you through a bunch of steps to diagnose your problem.

If none of that works, I would call Sony. They can probably refer you to an authorized repair dealer or may be aware of the issue and how to resolve it

This is just a guess, but I would bet that your video card is starting to break. Being that you have the original 60gb and its lasted this long, I wouldn't be surprised at all. My original 60gb broke about 5 months ago, and you have to remember you are treading on new ground because no one has had a ps3 much longer than you, which might explain the fact that there is little info about this problem on the web. Also, it taking 2 hours to start showing blue textures means it could be heat related. What happens when you start up the game when your ps3 has been off for a few hours?