I currently have a AMD Athlon XP 3000 with 2gigs of DDR400 ram and a ATI Radeon 9800Pro.

I can come up with about $300 and was wondering if I should just upgrade my video card to a 7800GS (AGP). How much of a bottleneck will my CPU be? Or should I just save another $300 or so and buy a AMD Athlon 64 X2 4200? I am going with the 939 because I don't want to replace my ram.

It will take me probably 6 months to save another $300 though.