Two things bother me about this; One, the case is very narrow at 4" wide, you may not be able to install a full size card there and two, the PSU is only 220 Watts, totally inadequate for the card you have in mind and you may have problems replacing it because of the small case.
hmmm the pcie-x16 slot is the top slot there. it looks like you might be able to squeeze an 8800 gt in there but it'll be real tight and the case and cdrom would obstruct air flow pretty badly. doesnt look like that power supply has a 6 pin header for pcie power either. I wouldnt try it.
best i can think of is the nvdia 9500 gt or ati 4670 cards
both cards look to be tight fits.