I agree with the Radeon 7500, I picked one of the 64MB AGP ones from newegg and it runs much smoother than my little voodoo3 that used to be in there. Mine cost around $70 or $80 so, I dont think it is the same one that you mentioned.
Here it is, although this is the PCI version, not AGP:
Radeon 7500 64MB DDR PCI