Muslims CAN marry to non-Muslims but that non-Muslim must atleast belong to another religion or have a belief in the existence of god. Unfortunately from what I know about pakistani people, they don't like their kids to marry someone who isn't a pakistani (some accept arabs), so it will be hard for you to get in with her family (i may be wrong as im arab and not pakistani). regardless the best thing you can do is to announce your feelings to the girl, if she accepts and reciprocates them then you should go speak with her family, maybe they wont be as bad as you think, you could go to them and confess about your feelings for their daughter, the biggest thing they will be worried about is about the upbringing of their grandchildren and whether they'll be raised in islam, you could try to reassure them that they'll be raised up as muslims and also ask them to teach you about their religion. maybe it would work out if they find out how keen you are to give it a shot. it's best if you do this as soon as possible.
P.S. if they agree to teach you about our religion and you dont believe in its teachings and not understands its beliefs then you shouldn't convert for her, it probably won't work out for you and you will have to live a life as someone else and who isnt truly you and you wont be happy. Also a liar will get caught at the end of the day so there wont be a point in pretending you are a believer.