Hopefully, you are both over 18.  If she loves you like you say, then as an adult she is going to have to make a choice.  He can't force her to go somewhere without her consent.  While I realize that her culture is different, she is going to have to stand up to her father.  Unfortunately, if she doesn't stand up to him and goes with him, then there is not a lot you can do except forget her.  Do not do anything drastic or stupid.  You could end up in trouble.  The next step is up to her.  Good luck!