Hired Guns are hard in general. First of all, they are paid to sit there chit chat, be nice to you, look hot, and to flirt. That's just how they earn their money. Granted she may actually LIKE you but...
-Most HOT girls don't tend to stay single very long at all. A few weeks to MAYBE a month is just about it. The whole breaking up with her BF two weeks ago...probably not a really solid reason. It sounds good, but in reality with the right attraction shouldn't be an issue.
-With Hired Guns you have to get past their shell and get them to open up to you about their personal life. You have to get around the "I'm a hot bartender" frame and get to the real person. This can be difficult with many because they are use to guys trying to do this. In order to do this it usually takes some very good DHV flash game, or being a regular where you get to know her better.
Good job asking for her #. It doesn't hurt anything and it won't be weird the next time you see her cause she wants to keep a customer.

Just keep in mind that until you really "break through" with her she is just talking you up like she's done 100 other guys at the bar.
Good effort sir!