I'm sorry but life's too short.
If she doesn't know her own heart then she'll break yours.
Its best to move on. You were likely a rebound relationship and you had way way far far too much invested in her than she had in you.
Your best bet is to move on.
I personally do not believe in 2nd chances. Even if she came back and resumed the love affair with you, in the end she'll leave you again. Maybe not for the same reasons as before, but since it didn't affect her the first time, she'll leave you again.
And if you get back with her you'll always be wondering if this is the last time you and she are together, or if she's still pining for her ex before you. The simple fact that she wasn't over her ex tells me right there you are her last choice, not her first. That's not a healthy sign.
If anything the next time she dumps you, you'll really be abandoned and let me tell you that when that happens, it hurts so much worse and in the end it'll f**k you up for life.
Imagine on down the line, every woman you see after her will never measure up to your expectations because you'll pretty much carry some heavy baggage around. And though its possible even probable that you'll fix what's broken inside you, you will always be worried about something in your future relationships.
This way you make a clean getaway. And if you meet someone new, give HER a fair chance, not like the crappy chance you got from your now ex-girlfriend. You don't want to rebound with another woman and do THAT to her, since its been done to you. So be on guard for that.
Finally, moving on is healthy. Letting go of the ex is the best thing you can do. Just cut her out of your life. Stop talking to her. Make her leave you alone. If she has regrets later, its her problem not yours. Don't let her vacillating back and forth ruin your future.