well, if you're leaving in 2 weeks let her know and just ask her to join you in doing something fun instead of "can i get your number?" first - something she normally doesn't have access to. if she does agree, then it's probably going to be more memorable that way. emphasis on the IF lol.
remember that they are real people with feelings too so make sure she knows your deal.
also, if she asks for money to hang out with you then you have your real answer.