I'll give you some advice you won't listen to: don't transfer to another college just for a girl. It's really not worth it. If you were married or have a kid together that is a different story. But if she's not even your girlfriend anymore, then definitely no. There are plenty of fish in the sea.

While grad schools do put some emphasis on the school you graduate from, the most important thing (I'm assuming you're talking about a PhD) is showing you can do good research and getting good recommendations by your professors. Getting decent grades probably wouldn't hurt either.

As far as getting a job is concerned, it really depends on what you want to do. If you want to go work in consulting or at an investment bank, then yeah, the school is very important and going to a good school will open a lot of doors. If you want to work at a startup, being able to get things done is much more important.