I'm with the others, get a tow truck and get your truck out of there.

What do they mean they "think they fried the second computer?" If they fried one I'd give them the bill for the tow and the new computer.

They either did or they didn't fry it and if they did, they don't have a clue about vehicle electrical systems.

There are a lot of good auto electrical shops if you don't feel you can handle this yourself. I will say though that you've got a lot of people here that are willing to help you through this if you want to try and tackle it on your own.