I'd say, if you can, junk all the tires, and get all 4 new ones. If you need to just get by until the end of the semester, you can get a set of 4 tires for like $100, plus installation, which shouldn't be much.

As i see it, it's a huge mess that nobody wants to properly deal with, and you're gonna keep getting pushed around until you put your foot down and make one of the shops fix it. They're the ones who fuxed up with your tires, giving you incorrectly matched tires, and they're the cause of your pulling problem.