Terjo2299 :
The add on slot is the expansion slot. There are three of them and that video card will not fit
so are they the small PCIE x1 (Small slots)
or there are three little slots, if that is the case and there are 3 slots it will fit because it only takes up 2 of those 3 insert at the back of your case, if it is the first you are kind of screwed because they do make a guy for that slot they are just very expensive or not as good because they are workstation graphics card.
http://lh4.ggpht.com/_XlySlDLkdOc/TJvSjY6bYqI/AAAAAAAAExw/_b2V82SAEZA/image_thumb%5B2%5D.png?imgmax=800