Your trans fluid level should be fine. As everyone has stated, it sounds like you are leaking oil from the rear main seal. They sell drip pans at auto parts stores for about ten bucks. Buy one and monitor the situation. If you are going to keep the car you eventually will want to get this fixed. In the meantime, spend the holidays parking in the street rather than your friends' driveways.
Oh yeah, have the seals on the top end checked before you have the work done.