If you've got an electric drill you could start drilling holes in the side pannels or if you've got a jig saw or drimmel you could cut some holes for more fans
An 80mm front fan should be fine for a couple of hard drives, but looking at your spec's it probably the 8800 that's pumping out a lot of heat.
Cutting a hole for a 120mm fan is fairly easy (a 120mm fan grill will cost a quid or two) Good places for additional input fans are, the bottom left of the side pannel or alternatively if your case is on a hard surface with feet, then you can cut a hole in the bottom of the case.
antec 900