How do I ask out a girl at her job?

There is this girl in my home town that works at the local video store. Whenever I am visiting, I always pop in and rent a movie for my folks and see her working. She is always painting or drawing and listening to 'indie' folk music and drinking tea. She is also an alternative girl with long black hair with the side shaved and piercings and tattoos, not to mention very pretty. The problem is, I don't know how to strike up a conversation with her to ask her out. She is always chatting and joking around with the customers, but I never know what to say. I once overheard her on the phone planning to go out for drinks at a pub near by. Should I frequent that bar? Do I ask what music she likes? Help! this girl is not the typical female!