|"Go to NEWEGG.COM, they've got a dozen or so AGP cards and most have DirectX 10 on them"|
I agree about newegg.com , but very few AGP cards support DX10. You're not running Vista so it doesn't matter anyway.
Look for a card that uses 128-bit memory. Don't waste your money on a 64-bit card & do NOT buy a card from BestBuy, Circuit City, etc. If you do, chances are you'll pay WAY too much.
Here's a possibility:
Or if you're willing to take a chance on "open box", here's the same card for less $$: