Adding videocard

Have a HP Pavillion a523x desktop, with a AMD Athlon XP3000+, 2.10 Ghz, !GB processor , and an integrated VIA/S3G UniChrome IGP display adapter. Want to add a video card with at least 128 MB memory so that I can use 3D online programs and software. Can it be done. And, if so, any suggestions.
Thank you
I have XP Home Edition