Battery or alternator

Our 98 chavalier started this morning and the battery light stayed on, we drove approx 10 minutes brought the car home and then it promptly died in the driveway. The car was not used all weekend. I am guessing alternator because if we had left interior lights on wouldn't it probably of been dead from the get go? What should be our course of action to see if it's battery or alternator?

well actually if the lights stayed on too long it could of just fried your battery and it was able to run for a while casue the alt was cookin overtime. best advice, get them both checked out, but if the alt is bad change your battery while you are there