Do yourself a favor and go get an 18 gallon plastic tub.
You like soda? Well if yes, empty a few (6 to 8) and fill them up to within 1" of the top with water; freeze um.
Put your fermenter in the plastic tub and fill with cold tap water, just don't fill it so high that your fermenter starts to float.
Put a couple of your frozen water bottles into the tub and do as suggested earlier with the wet towel and fan.
Your temps will stay around the mid 60's this way and your fementation will be controlled.
--Or--
Drop the cash on a temp controller (Ranco, Love) and use an old chest freezer or extra fridge.
However you decide to do it, controlling your fermentation temperature is vital to producing great beer. Also doesn't hurt to get one of those stick on thermometers for your fementing vessel.