The mobo have a PCI-E line x16, so, you can use any GPU available on the market the problems is the PSU, CHECK YOUR PSU 1st before buy a new GPU. Usually the PSU of those pre-build rigs isn't good or not good enough for power a high end or middle end decent GPU.
That pc has a250 watt power supply. Saint19 is correct, you can use any card out there, but not until you upgrade your power supply with something decent.
Whats your budget? We can make some suggestions if we know what you can spend. Also what screen resolution do you use?
Right on.. Thanks for the knowledge.. Well just purchased the Adobe CS5 Collection cause i'm heavy into design.. I also use Blender and 3DS Max..
The problem is the rendering.. It takes forever and also not so smooth..
I've already looked into a better processor, now i'm just looking into a better GPU..
A budget isn't really an issue.. But i'm gonna throw out a number.. $200-400..