video card

help finding right card for my computer.specs. windows xp
home socket
939. athlon 64 pro. northbridge nvidia gforce 6150
southbridge 430.
front side bus 2000/1600mts.dual channel memory 4x184 dimm
sockets
2[512x512] memory.power 500 watt. amd64 3700 pro socket 939.
pcx video
integrated nvidia geforce 6150 processor. motherboard asus
a8n-vm
nvidia nforce 4 chipset pci express with ddr. looking for a
card for
this setup around $100.00  any suggestions?
thanks....richone