I have been there.

I know how difficult it is to date someone who is not of your beliefs. I was in a relationship for 8 months, which I broke off last month, simply because we were too different (among other things). It causes so many problems.

I think you should pray about what God would want you to do. Perhaps he will convert to Christianity. Perhaps not. Just pray that you will put God first, trust in Him, and put this entire relationship in His hands.
As for being "less Christian", if you have a campus Christian group, you should join that. It will help your faith to grow if you are surrounded by other Christians trying to keep the faith. I know how hard it is to keep faith in college.