alright, im back, sorry for not responding sooner!
I hope I can still help.
Most cards plug into your motherboard (mobo) by a PCI-express slot. PCI express now is mostly in a 16x slot (I think that means 16x faster than original PCI slot ill explain more later). Although If I remember right, a few months after PCI mobos came out they had a PCI 4x as well. You also have a pci 1x or x1 slot, but thats a different story and not a concern to a gfx card in your case.
Now graphics cards can plug into, PCI slots, AGP slots and PCI-express slots. This is important, PCI is slower than AGP, AGP is slower than the new PCI express. But now, they dont even do PCI graphic cards, so PCI express is just commonly referred to as PCI.. So try and not be confused, I know it is, in fact I was at first when I started typing this.
http://www.abit.com.tw/page/en/motherboard/motherboard_detail.php?DEFTITLE=Y&fMTYPE=Socket%20754&pMODEL_NAME=KV-85
From the looks of it im going to guess this is an older computer. Its says you have 3 PCI and 1 AGP slot. Thats the old PCI that you have. So your best bet is to get an AGP graphics card. I dont remember the cut off when they stopped making AGP cards, they actually probably still do, but a hot card that was offered in AGP was the bfg tech 6800 GTOC. You should be able to still find these on ebay and for cheap.
This is a start, theres tons of shopping you can do, but you need a AGP card. And make sure it has DVI out on it, the 6800 I mentioned should have it. If you arent really doing gaming anything like that card or even less will be more than enough performance to do household PC tasks.
Oh man beware,
http://www.google.com/products?hl=en&q=bfg+tech+6800+gt&um=1&ie=UTF-8&sa=X&oi=product_result_group&resnum=1&ct=title
look at those old gaming comps that never sold that people still think are worth over $1000!!! haha you should pay like $40-50 for this card used, if its even still out there. Still, that should be your price range man, any card for more and you arent going to need it if your not gaming. Let me know what you find, or if you need anymore help.