Call her in a couple of weeks and tell her you are willing to give her another chance. Laugh your ass off before calling. You want to sound as fun and nonconfrontational as possible.
If she says something about the last time you spoke, or if you have to leave a message, I would throw out that the last time was awkward for both of us.
If I was you leaving a message:
Hey ________, I haven't seen you in a while, and I decided to give you another chance (smile while you say it). Things were awkward for both of us last time we talked, but no big deal. Hear from you soon or, in case this was a bad time, I will try again later.
I have failed more than most men have tried.
Every woman you pass up is a woman you will never have.