Welcome to af.
Get a used transmission at the auto salvage. You will spend about the same amount of money replacing the chewed up parts. Very possibly more. You should be able to get a used tranny for about $350 to $500. The reason I am suggesting this is that if you miss one chunk of stray metal and it gets into your rebuild you are going to be po'd. If you go ahead and fix it put in new seals and synchronizers. I wouldn't attempt a tranny rebuild. There's too much that can go wrong. I hope you are a better mechanic than I am. Good luck with whatever you decide.