Rage, I don't think a GF3 or 8500 (AGP anyway) would work, considering this.
AGP Status: Not Available
If AGP were available in this computer, I think they'd have one in there instead of a PCI. Of course I might be interpreting this wrong. For her sake, I hope I am.
If it turns out that she does have AGP available then I'm all for your recommendations. She's running Windows ME by the way, but more memory would still be worth it.