The key to that card is that it's an 'SE' model which is really saying it's the cheapo 9600 as compared to the XT and Pro models. The card is approximately 5 years old, at least (2003-2004). The only benchmarks I can find for the card are quite old, mainly Call of Duty 1 and Flight Sim 2004, the card did 30-50 avg at 1024x768 resolutions.
I've got a gut feeling your motherboard has a PCI-E slot, but it could go either way. The Nvidia 6xxx series chipsets appeared in 2005, but you can still find them today on off the shelf computers. My father's HP he bought in Aug '08 has the 6150 onboard chipset.
I can't say for sure, but by chance if your motherboard has an AGP slot, I think the 9600SE may be a very small improvement, if any at all. It only has 128mb if RAM and its only DDR, nothing faster, you onboard (though it does share system memory) should have more than 128 (probably 256) I believe it was a $50-60 card when it came out.