Clean the house until it is spotless right now. Seriously.
If the house is clean when she gets back, she won't care what the hell you did or how much money you spent in the interim, at least as long as you brush your teeth and shower off before she sees you. So get that part out of the way right now, and then just contain the rest of your weekend's filth to a few narrow, easily cleaned up areas. You'll be golden.
I can promise two things: A) the clean house gambit works, and B) cleaning it up now is going to suck less than cleaning it up on Sunday afternoon when your head is pounding and you want to throw up the whole time.