Eh? Most games today are GPU limited and have been for a few years (since core2 I would say lol). I recently bought a cheap Q9550 because I had the upgrade itch and I didn't want my dual to be the limit when I upgrade the GPU but so far, there's not much of difference except when I play games, surf or study the CPU usage is 5-10% instead of 15-30%.
Again, if money is such an issue, why stay Intel, that cpu for ~400USD (are my exchange rates that far off?) when you could get so much more with that money (like a much faster AMD CPU/MB combo