Luc, the integrated graphics are what they say--Intel. Also complete and total crap.
Homedad, first you need to determine whether that system has an available PCIe x16 slot. Now, the integrated graphics it's using now are ont he motherboard, so they're not taking up a slot, and you wouldn't be swapping out.
If you have that slot open (it's a long slot, longer than your standard PCI, and much longer than the old AGP graphics slots), then it's just a matter of picking a card that suits you. If you're gaming, then I'd get a Radeon 4850. If you're just going to use it to watch blu-rays (for example), get a lesser card; perhaps a GeForce 9500GT.
