I want to do some general gaming like GTA 4/FSX at a good 30/58 FPS with Medium-High settings, I currently have a NVIDIA GeForce GT 610 OC'ed ( I know, very entry level) I am planning on getting the GeForce GTX 650 http://www.overclockers.co.uk/showproduct.php?prodid=GX..., is this any good? My budget is £130, though if there is a better option I can go a bit more.
My MoBo is compatible with PC-I Express 2.0, so if you could find one compatible it would be much appreciated.
1) 2.0 & 3.0 are fully comparable & compatible. You can use just about any GPU you have the power to supply, so don't worry about that.
2) Tomshardware (the site you are on) does a monthly article on best gaming GPUs. check the article to start.