You say you take graduate level courses, so I'm assuming you go to a college.
Now, this may be hard to deal with, but here's my suggestion:
Find a club on campus and meet people there.
Sure, they'll most likely be undergraduates, but at least she'll know that they share a common interest, and she can go and be topically geeky once a week or every couple of weeks. I used to go with my buddies and watch anime every Friday, see what new videos had come out, what the other guys had picked up. I enjoyed it, and eventually I dragged my girlfriend at the time along and she enjoyed it, too. (I need to find something like that again, really.)
Anyway. Campus clubs may be just the answer you're looking for. Good luck!