How do I ask out a girl I have known for a while?

Depending on how long they went out, she'll need some time to get over him and get into you. Right now, she needs a shoulder to lean on...you could play that role to show her that your sensitive and there for her...that could backfire, though, if she puts you in the friend position permanently so be careful not to be too sweet. Example, if she's talking about something he did, you can say, "He's such an asshole, you're better off without him" but NOT, "Oh, baby, he didn't understand you, you deserve so much more than he could offer" - does the difference make sense? Be strong when she's weak and say things that help her get over him faster, not cater to any self-pity she may have right now.

Well my friend, that's easy but needs courage. Call her one day, talk for a bit, usual stuff. Then say something like "would you like to have drinks at [someplace cool], she deserves a martini". When she asks why , tell her that she was proud of her being strong enough to break up a relationship because it was hurting her and she made the right decision.