in the picture of ur case, there are 4 fan slots, 2 fans they give, a side and top fan and there are 2 open one that they do not give u, one is the 120MM back on, the othert is the 80MM front one, look at the pics.
Case fans are all pretty much the same, unless u want them to push alot of Air then ud look for ones with high CFM rating or if u want quiet ones u look for ones with low DBA ratting.