Best AGP Video Card in 2013?

Hello,

I need a new AGP video card; wondering what is the best one I can get, for my PC:

I have a Dell Dimension 4600 desktop.
Pentium 4, 2.4 GHz
4 GB Ram
AGP 8x
Windows XP, SP3
Antec 500w Power Supply

I had an ASUS ATI Radeon AH 4650 1GB graphics card that has quit. It replaced a PNY nVidia GeForce 7600 GS (which actually seemed to run the rig better than the Radeon, but it died after several years so I had no choice).

So I need a new AGP card (cannot buy a new PC at this time, but would like to keep this one running for maybe a year more).

I've seen ads for:
HIS Radeon HD 4670 IceQ Native HDMI 1 GB DDR3 AGP Graphics Card (H467QS1GHA)

and recall the nVidia 7600GT and 7800GS being good. I prefer nVidia over ATI but if there is a big difference then I'd go to the ATI again, if my rig can run and utilize it fully.

I can see nVidia cards on eBay for $30-$150 (many used); ATI 4670s are similarly priced. No local stores have these cards.

Any constructive input would be greatly appreciated.