You need to get serious in drawing the going in the toilet good, going in your pants bad line. I'm not talking about spanking or anything like that, but you have to be clear that this is a big deal all the time, not just when she feels like it.
With my daughter we used candy as a reward for going potty. And that was the only time she got candy until she was fully trained, period. She got smarties or gummy candy for going pee (one piece) and chocolate for pooping (3 M&M's or a Hershey's Kiss) This was the same every where she went, no matter who she was with. For about six months that child earned every sweet that went into her mouth.
I also stopped changing her after about the third week. The first time I realized that she was going in her pants because she didn't want to get up and go to the toilet was when she got her clean underwear and change of clothes handed to her and mommy watched while she got herself changed. I continued to help her get dressed in the mornings and if there was a clothes change needed while she was dry, so that was another reward. During this time we did morning and night baths and I kept diaper cream on her to keep her from getting a rash from not being cleaned as well when she did it herself.
The other thing that helped with my daughter was a little competition. We happened to have four girls and one boy all potty training at her daycare at the same time. Plus a few older children who were already trained but willing to play along just for the candy. Since the only way to get a treat was to use the toilet, there was a line outside the bathroom all day long, even when it wasn't potty break time. Some of the kids ate their candy right away, and others held onto it just so they could rub it in that they had candy and so and so didn't, but every kid was consistently using the toilet at daycare by the end of three months.
My daughter is six now and she still heads straight for the bathroom at my grandma's house and then asks for her reward (grandma always has the fancy candy with the goo in the middle)