At this point I wouldn't read into it too much...
1.) She is a girl and sometimes women just enjoy being nice and flirtatious for a multitude of reasons. It can often be mistaken as interest by the other person
2.) She is part of the staff--it is her duty to be nice to you because she is trying to maintain a professional image. Ever hear the old saying, don't mix business with pleasure? This one pertains to that.
3.) There could be a possibility that she IS interested. The only way you would know is if you make the effort to flirt with her a bit too. Just make sure you have better evidence of her interest to go off on before you make such a move
Please answer mine :) link