No guy gets my personal phone number, unless I'm interested in him, or I'm collaborating with him on a contract, or he's coming to my home to fix something electrical. But then again, I don't work for a mobile phone service provider, maybe she can change her number for free every time she gives her number out to someone she doesn't like...
I'm guessing she's either interested in you, or she's insane. How high did she rate otherwise on the insanity meter? You mentioned that she talked about her ex a little... did she say she broke up with him because he was too clingy, or because he had a restraining order on her? I think if she passes the initial screening (job - check, shoes-check, ability to smile and make pleasant, relevant conversation-check) then she's not Level I stark raving mad and she's probably just... interested.