Product Specs Sheet
Your system apparently has one PCI-Ex16 2.0 (x4) slot and one PCI-Ex1 slot. Given the case size, you would be limited to low-profile/half-height cards. Given your low-end, 220 watt power supply, you're looking at only the very low-end graphic cards, none of which will give you the performance you're looking for.
Recommendation: None (sorry).