I think that you will find that most video cards are backwards compatible. You only need a x2/x8 agp slot to get the all singing and dancing to work on the video card.
I havbe done some checking on you machine and found that it is x2 compatible...
Graphics chipset
8 MB-nVidia Vanta LT-2X AGP, 80/100 MHz Eng/Mem,128-bit TNT2 3D graphics processor, 1280x1024 resolution, 32-bit color and 250 MHz RAMDAC, 32-bit Z/stencil buffer, DirectX and OpenGL support
Graphics bus 4X AGP (AGP 1.0/2.0 compliant)
There is another chipset available though, so if this is not you, or want to know more follow this
LINK, and check the specifications...
Hope this helps...
<edit:Graphics card updated info>