Wow way to flamebait darklordjames. But it is aparently you who doesnt know a lot about RAM as you didnt even address the concern I brought up over his RAM. Size wise is fine but his speed if it really is PC3200 is not. Which is the point I made above.
And if you look, YOU have the slightly cut down version graphics card, not him. He has a GTX260, you have a GTS250. GTS cards are lower than GTX cards, even if he does have the first generation GTX260...
Now if you look at the point I was making, PC3200 is generation 1 RAM at DDR400, which is 200MHz in speed. Lets say he has great PC3200 RAM, that means he has timings of 2-2-2-5. Uncommon back in the day, but it did exist. I actually own a pair of sticks with those speeds and timings. However, those timings was only common in 512MB sticks (still rare, but of the sticks that existed, they were common in 512MB sizes), and incredibly rare in 1GB sticks. Which means he either spent $400+ in RAM way back when or he has lower grade timings, which is much more likely. But even if he had the best timings of DDR400 RAM, his bandwidth would not be enough to provide the CPU with adequate data and would be a large bottleneck to his system. Just look at it, he has a quad core with at LEAST 2.6GHz probably higher. And he has a modern graphics card requiring large ammount of data from the CPU, which does have enough power to give the graphics card that data. But then he has incredibly low speed RAM, starving the CPU for data and slowing the entire system down. For a system like his to not bottleneck severely at the memory, he needs at least DDR-800, preferably DDR-1000 or higher. His PC3200 RAM is most likely 2.5-3-3-7-1T timings, so cheap DDR-800 would give him 5-5-5-15-2T timings, which would allow him the same nanosecond latency for his memory, but would give him double the bandwidth. If he got DDR-1000 (or 1066, etc) then the timings would most likely be 5-5-5-18-2t which would actually be faster latency wise but have even more bandwidth. With more bandwidth the CPU wont be choking for information all the time, which will allow it to feed the graphics card with all the information it needs when the card needs it. This will help a lot with the minimum frames per second.
Now, if he is going to upgrade his graphcis card, which I dont recommend, then the only card to upgrade to that would offer a significant performacne increase would be an Nvidia GTX295 or the new AMD 5870. Those are the only cards that would be a large enough performance difference to justify an upgrade at this point. Personally I would choose the 5870 out of those since it is a single card solution and not SLI on a card. But I would definitely recommend waiting until some more AMD cards are released and Nvidia releases their new cards as well before thinking about an upgrade. If you are going to upgrade, and you really do have PC3200 RAM, then get a new motherboard and some faster RAM. Thats where you will see a large performance difference.
Next time learn more about what you are talking about before you flame other people. You arent right about a single thing in your post.