Well, you’re looking at a few hundred all in but why not give RAC etc a ring? I doubt they’d leave a lady stranded in a car park. Most important thing is to get the thing looked at and diagnosed. It might be simpler than you think.
You’re correct about towing an auto - I thought maybe just to get you out of the car park.
I’m in Aberdeenshire, so can’t help you directly. While you wait, here’s a story - I had to fix just this problem for the wife. She was working 1 1/2 hours away in Inverness, and as she got towards work, the headlights dimmed, car faultered and the HDC/ABS/TC and battery lights came on. Sensibly, she switched all the electrical loads off and crawled into the car park, and gave me a call. Thankfully, I had a spare alternator, and got the tools together and drove up. Amid some odd looks from the staff, I tiddled away at the car and swapped out the alternator. A quick jump start later and all was well - no new battery needed even.
And that wasn’t even the first time she’s abandoned a dead car in a car park for me to fix. Before that, a prop bearing disintegrated and she dumped the car in an M&S on the way to work - got the bus the rest of the way. She now tells both of these stories with a chuckle, in contrast to the tone of her phone calls to me at the time.
Moral of the story - what seems like disaster now will become an amusing anecdote in years to come.