I've had the battery light come on before and make the car die because of an alternator failure.
The alternator stopped working, so the battery wouldn't get charged AND was the only provider of electricity to the car systems and therefore depleted completely before long.
Did you notice what the voltmeter showed on the dash?
If you are able you can bring your battery to a parts store (Advanced, Zone, etc) and they can tell you if its empty.
If you're handy great, at the dealer around $1000 - which is where AAA had to tow me on my trip.
2001 Audi A6 Avant Quattro 2.8