Red battery light on.Help!

[four.8is]

well, good thing i was close to home when I noticed the red battery light on...

turned around to hook it up to DIS and it gave me a bunch of odd errors like

-relay, heated rear window-faulty
-steering wheel column radial - transmission fault
-electronic braking-force distribution fault
-brake light, right, faulty

the car doesnt start anymore...

I know a low battery throws a bunch of electrical errors but the battery is one year old.

I'm thinking alternator? How can i be sure?
I read that an instantaneous red battery light is often an indicative of a broken accessory belt.

Haven't checked that yet...but i suppose you lose power steering, alternator ofcourse and water pump that leads to overheating...well i had power steering, didnt drive enough to overheat, etc

Ordering an alternator will take a while, ill be stuck in the house this weekend...not fun at all.

How hard is it to replace the alternator on a 4.8?I've only done it on my E39 530i and that was pretty simple.

If it turns out to be the alternator, other than replacing belts, what else can I do "while in there"?

thanks guys i really do appreciate all the help i can get.