If you are Just trying to switch out the fans already in the case; if there's not a bigger set of holes (for 140mm) then I would say add a 13 blade turbo fan (Aerocool Shark is a great one) It will get you a great current. If you dont have additional holes you might want to throw 30-100 bills to just buy a better flowing case.
After looking at your case though. You only have the one port. I would say buy a new case man. http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1927343&CatId=1509
Great Free-flowing case.