According to
this, your current graphics are integrated and you have a free PCI-Express slot that can house a modern video card. As Midean said, though, your power supply may be a concern as well. That site doesn't list the specs for the power supply, so I will try to find them elsewhere.
EDIT: I've looked at a couple other sites (including
this one, which both show it having a rather shitty 300W power supply. While it MAY run a
very low-end video card, I'd be afraid to hook
anything else up to that system without purchasing a new power supply as well. If you plug something in that draws more power than that PSU is capable of outputting (keeping in mind that the PSU's these branded systems have are typically crap that can't actually put out the amount of power they're rated for), you could fry your PSU, fry your entire computer, or even start a fire =0 (I've seen it happen to).