Hi C.,
I have boys, so I know there is a difference, however, my oldest is five now. He pee'd in the potty at three, and it took a year before he would poop in the potty. I did the same, charts, chocolate, stickers, crying, begging, fighting!! I knew I had ruined him for sure. My mom's best friend, a brilliant woman, said to me at my height of despair, "Do you know any adults who are not potty trained?" Hmm, no I don't, she told me each child has their own schedule, the more you worry, the more they need to take control. Relax mamma. don't listen to the outside pressure's of the world that say she should be doing this by now or that by now!!!!! You are okay! Also, I bought Elmo's potty dvd, the boys both loved it and watched it over and over, but it was still a few months before success.
My oldest went to pre-school, he had to be potty trained, and it was barely happening. I think being around the other kids going to the potty helped too.
Now both boys are happily out of diapers, pull ups, no accidents, except missing the toilet bowl once in a while, but I hear that is a life long problem.
Good luck, and really, relax, be good to your brain, it will all happen in time.
K.