if your going to get the aa out they will be able to tell for sure if its the head gasket or not. in my experience you get a puff of white smoke out your exhaust not steamy windows!!! take the oil filler cap off and check for what looks like mayonaise around it, you can also see this on the dipstick, thats a sure fire way of telling. you can also smell it in the coolant and the aa should be able to test the coolant for contamination. not to put a downer on the whole situation but how much??? i've done my head gasket had the lot off, skimmed and back up and running in a day! first time i've tried anything like it as well so god knows what thier hourly rate must be.
good luck all the same, and don't go selling it just yet!!
