my advice really only applies if you think this is a girl you wouldn't mind spending the rest of your life with.
i'll tell you this, speaking from experience:
i left to go to school far away from my long-term gf at the time. we agreed to stay together and try to make it work (and we were sure it would). but it was too hard to be away, and rather than break it off, i returned home. well, returning home was the right choice for a number of reasons, but our relationship was never the same after that. we didn't break up until a year after i came back (we were even living together at the time), but mark my words: i lost her the day i said goodbye and got in the car to drive to school. it doesn't matter how rational people are, there will be underlying blame and anger because you left her, because you chose school over her, because your relationship wasn't the most important thing, etc etc. college is a time when people are changing very quickly, when there are huge psychological leaps being made. if you don't make those together, you'll make them in different directions. the girl i came back to was not the same girl i left.
you have to look at the big picture, and school is not the big picture. there are more important things in life than school or financial success, and one of them is love. people place way too much value in this society on whether you are being "successful." the real successes are when you find soulmates. when you find one, hold on tight. besides, it doesn't sound like this closer school is exactly a hell hole. my advice is to stay. look at it this way: you can always transfer to the nice school later if you change your mind. but i'm telling you that if you leave now, the choice is final.