Wow bong hitz, your going about this all wrong. Your dad is away for a week so you can have an epic party one night and you will still have a week to clean up. My advice is this:

Get a keg
Tell everyone about the banger at your house and tell them to bring friends
Charge guys $5 at the door for a cup. They can drink as much as they want. the ladies are free

If enough people go you will actually have made a profit off selling cups and you will have had one hell of a party. Just pray nobody throws up on the carpet