Dead battery and Dead alternator

The battery is drained because the alternator isn't working, so the battery is not being charged. This is what I've been told after the battery place here did a check on the alternator.

I had a new battery put in yesterday, and by today it is once again dead. The car was not run the entire night. Anyone know how long a normal car battery should last without a charge?

While I would love to think the Sirius system I put in two weeks ago has nothing to do with it, I'm very suspicious.

The unit does turn off when the key is turned off. The controller shuts down when I turn the power off on the car, so I'm assuming the receiver shuts down as well since they're on the same power. That's why i'm kinda stumped here. How can it be a drain on the battery if it's not on, ya know.

I unplugged the power from the receiver yesterday, just in case, before the new battery was put in, but the wires in the dash are still connected. Would those wires still be a drain on the battery even though the power is unplugged on the receiver itself and the car had only been turned on once since the new battery was put in?

The tow truck lady said it looked like I should have two ground wires going. I currently have the Sirius ground spliced into my dashstereo's ground. But i'm not sure what good an extra ground would do.

The alternator does have 109,000 miles on it...so I'd like to think it's just time for it to go. But the timing is very interesting.

The car is now sitting in the service center's lot, so I'm hoping they can figure something out.