broke my alt...????

Sorry to hear about the Grandmother.....
There is a nut under the nut that holds the cable on that you should be able to tighten. What worries me is what caused it to loosen in the first place.
You can get an alt from a mid 80's van that uses a v-belt pulley. They come in the 90A and 120A variety, and as long as you run a additional power wire from the alt to the main relay, you shouldn't fry your ammeter....BUT I'd bypass it just to be safe. I'm running the 90A version on my /6 with only mild modifications to the alt mount and tensioning slider.