You need to determine if your motherboard has an AGP display card slot. you'll need to open up the case and have a look. check the picture I posted in this topic:
http://www.daniweb.com/techtalkforums/showthread.php?t=12988&page=1&pp=15
to help you identify the slot in question. If it only has PCI slots (the white ones) then I don't consider adding a display card is worthwhile.