Let's break it down simply. If you want to see an improvement over a 8800 GT you will need the following cards: GTX 260, GTX 275, GTX 280, GTX 460, 4870, HD 5770, HD 4890, HD 5830.
All of the above perform significantly better than a 8800GT, but with the exception of the 5770 require quite a bit of power. Some of them you could get working on your current PSU, but there are so many factors limiting you at the moment (PSU, CPU, Monitor) that if you want to break into the graphics big leagues and not waste your money, I suggest getting a new system. If I were in your position I'd sell my current system and since it's not too bad I'd get enough money towards my new system that it wouldn't hurt the wallet too much. When you're choosing a new system then you can design it with a high-end card in mind and get the MAXIMUM bang for buck that you're looking for!
Otherwise you face the prospect of sticking in a card that would use up A LOT of your juice (perhaps producing instability, but perhaps not), and that would give you....5? 10 more FPS? When it could really be giving you 20 more if it were in a better system?
I know the position you're in is not easy, but the best road is to upgrade your system. It has to happen sooner rather than later, and I'd do it while I still can get some decent cash back for my old system.
Let's break it down simply. If you want to see an improvement over a 8800 GT you will need the following cards: GTX 260, GTX 275, GTX 280, GTX 460, 4870, HD 5770, HD 4890, HD 5830.
All of the above perform significantly better than a 8800GT, but with the exception of the 5770 require quite a bit of power. Some of them you could get working on your current PSU, but there are so many factors limiting you at the moment (PSU, CPU, Monitor) that if you want to break into the graphics big leagues and not waste your money, I suggest getting a new system. If I were in your position I'd sell my current system and since it's not too bad I'd get enough money towards my new system that it wouldn't hurt the wallet too much. When you're choosing a new system then you can design it with a high-end card in mind and get the MAXIMUM bang for buck that you're looking for!
Otherwise you face the prospect of sticking in a card that would use up A LOT of your juice (perhaps producing instability, but perhaps not), and that would give you....5? 10 more FPS? When it could really be giving you 20 more if it were in a better system?
I know the position you're in is not easy, but the best road is to upgrade your system. It has to happen sooner rather than later, and I'd do it while I still can get some decent cash back for my old system.