for what purpose do u wanna buy graphic card
and ur motherboard wont support a good graphic card either
get a new motherboard compatible with pci express 16x which may cost around 6k
good graphics card like 8600gt for 8k, 8500gt for 7k(from xfx)
or ati hd2400 i would prefer ati because it has hdr+aa enabled which will cost around 8k good luck