Budget Woes, but need to upgrade current Socket 754 System

Hi All,

Here are my current specs:

AMD Athlon 64 2800+ (S0cket 754)
1.5 GB Crucial Memory
ATI Radeon 9800 Pro
MSI K8N Neo Platinum (MS_7030)
Antec Tru Power II PSU
160 GB SATA

I have a next to nothing budget, so wont be able to get a new rig. I'm hoping to upgrade this just enough to last me anohter 12-18 months.

Here are a couple of things that I'm considering:

Upgrade the Proc to the AMD 64 3700+, ebay around $150

Graphics card, up for options here, but looking at the ATI Radeon x800XL, the refurb one they have avail on there site ($119) although seriously considering an upgrade to the 7800 GS AGP.

Would the proc be too much of a bottleneck? Should I go with 6800 (one of the varieties). I know that this system is old, but I wont have the cash for a major upgrade for at least another year.

Budget: 300-400.

Thanks!

Jim