I'd be leaning towards the problem being your alt crapped out on ya. Had the same problem with same symptoms in my mustang. Drive a few feet and car died. Turned 1 or 2 times then that was it. Car wouldn't charge the battery but battery could be charged via other means, jump, charger, etc.
If you get the chance I'd run to a local parts shop like pep boys or something and have em check your battery. Mine kept dying in my 535 and I took mine in. Came to find out my battery had a cell gone bad. I had intermittent problems with starting mine. Usually ran fine but sometimes didn't want to start. Others it would be fine. Anyway yours seems old enough to have it check/replaced. I paid 60 for a new one and was nice to have the peace of mind.

I guess what I'm saying is it sounds like your alt but your battery is also old enough that it might also be adding to the problem.

Just my 2c. I only go by experience and have no further knowledge of cars other than my own and my interest.