Take the cover off and have a long look at what is there. Then research installing pci/isa cards on the Internet... look at motherboard layouts... and if there is no pci slot, throw the computer away! If it is a 2/2 board like you say but a PCChips motherboard, still throw the computer away!
<font color=red><b>To reign is worth ambition though in Hell:
Better to reign in Hell, than serve in Heav'n.</b></font color=red>
John Milton, <i>Paradise Lost</i>, II 262-263