How to get back a good friendship when already broken? She doesn't want to talk?

I think you give it time, and if she doesn't want to talk, and apologize, then leave her alone.

You give it time and space. If a person does not want to talk there is really nothing else you can do.

Move on! Talk to her and say: "What do you want?". Give her some time to decide but most of all give her space. We're both in that situation now so I can give you some advices. Did she tell you why she isn't talking with you? If she didn't then start pointing out negative things about her. For example, a good friend would never throw away a relationship just like that. Maybe she isn't truly your friend after.
BUT RENEMBER that the most important one in all this history is you! Most of all keep your honor and dignity and don't crawl after her. That will make everyone think that you're ridicolous and after a while you'll think the same too. Trust me... I know what I'm talking about.
Hand out, talk with people and see that as her problem and her fault. If she does tell you where you went wrong and still mad at you, then great! Learn from it.
But don't get as stuck as I am. Do everything to get away from her. Also, if you really liked her (as a friend), you'll do one little thing that she isn't doing: respect her decision!

Take 30 minutes of your everyday life and spent that time thinking about her. Then forget her until the next day and focus on other things. If I can help you on other way just ask.
Good luck!