Oh man - you are so in need of a bike that works, especially if you enjoyed riding on one that --- had issues! Definitely search out Craigslist, perhaps local papers (my local papers don't really have much), - but also Google local Bicycle clubs - my club has not only a side listing of what they have for sale (my club is 450 strong so there's usually something out there for sale) - and also I have one - if not more LBS that have some used bikes for sale.
the college may even have some tips on bicycles, if not even some people available who can help perhaps with the bicycle problems.
I work at a 2 yr school here in NY and we've gone "green". There are a serious bunch of us commuters here who, with the help of a Dean who bicycles as well as many others, encourage bicycling as a means to commute, live well and also be a non-polluter and enjoy yourself.
I also know of one - if not two 4 yr schools around here who encourage the same (bicycling) and have some programs set up for maintenance and/or bicycle sharing.
check 'em out!
Meanwhile - Welcome aboard!