Cant see the CPU upgrade giving you that much extra performance. The GFX card is your weak link. What games are you trying to play? Also make sure your psu can take whatever upgrade you choose. I agree with HD 4850.
Thanks a lot. I will get a 9800 GT in this case.
At the moment, I am playing Fallout 3 and Deadspace, going to upgrade for upcoming GTA 4, Left 4 Dead.