a screw from the alternator where a electrical wires connect to broke what are my options

Yes but theres still a little bit of screw sticking out i was advised to solder it together?

I doubt solder will hold. Try using a small drill bit to drill a hold then a screw extractor to back out the old threaded rod. It would probably be easier to drill a slightly larger hold and tap new threads.

Scratch what I said before. Just took apart an old alternator I had in the garage to take a look. It's only four bolts holding the two halves together. Inside, the terminals have plastic insulators attached. If you begin drilling you'll mess it up. The studs are removeable (it appears) from the inside. Just do not loose the insulators and make sure to reinstall them with a stud of the exace same size. That's as far as I went with disassembly. But the case came apart easily. Just make sure to use a marker across both sides of the case for reassembly. Visually, it appears you could reassembly the case 180 degrees our of allignment.