Don't be an ass.
If it is really a "window" AC then just go buy a new one, the small ones are under $150 and the biggest ones are only in the $300 neighborhood.
If you're renting from an apt complex or something like that they will almost certainly replace your "broken" one with one just as old and crappy. If you are renting from a private owner, they would probably split the price of a new one with you.
Or, duh, just buy the new one and take it with you when you leave. I'm pretty sure they didn't do a bait and switch on your AC unit when you signed the lease.