So there is this girl...?

I've known this girl for a few years now (she is a family friend). We get along so well and have a ton of fun together (and flirt a lot). I never had a chance with her because she lived in another state but I've always had a crush on her, she finally moved up here but had a boyfriend. They just broke up 2 days ago (they dated like 3 months) she is very upset but I want to make a move soon before she iis taken again. However I need to wait long enough so I dont get denied over her still being sad. How long should I wait? What are something I can do to start moving from friend to boyfriend? And any creative "ask her out" ideas are also welcomed!!