Use the big girl undies to bribe her. If she knows how to go on the potty, i.e. gets the control of the muscles, now you need to put her on a schedule and cultivate the potty habit. The schedule will then lead to her naturally taking herself off to the potty without your help. But that takes time with little ones, so you have to be patient.
If I was you, I'd pick a day and then just move forward full force. No going back, no pull ups. Get some cloth trainers, and make it your mission to get her to the potty before she has an accident.
Also, every day put her poop in the potty, and when you let her flush it, tell her that pee and poop go in the potty.
Potty training is correlated to parental motivation. My daughter was fully trained(including night) by 23 months, because once she showed signs, I decided to help her learn what she needed to learn --kind of like all we do to help them walk. Now at 25 months, after 6 months of me taking her to the potty, she takes herself and/or tells me. It was worth all the time and effort, and you should see how proud she is of herself. Besides, she has no desire to be wet or to sit in poop. Yuck.
A few rules: praise works the best, so develop a potty dance and throw her in the air when she is successful; and two, never ask her if she needs to go, at least not yet. Ask, "do you want to go before snack or after snack? do you want to go on mommy's potty or on your potty?"
By the way, my daughter finished training 4 weeks after her brother was born. I think it helped a lot, because she wants to be a big girl, not a baby, so we really pushed that factor with her and it really worked.
Another gfriend of mine is training her just 24 month old with a 4 week old in the house and is having great success.
Regressions are going to happen, my daughter had tons, but as long as you commit to it and stick with it, you will get there sooner rather than later. You can either do nothing and let her learn it all on her own --which could take another 1-2 years, or you could put in some effort now and she could be trained in a matter of months.
Your daughter is most likely pushing back because she is uncertain. She is learning a very hard thing, with lots of components. So you need to just be patient and give her lots of opportunities to figure out what she needs to learn. Once they understand the control, then they have to learn timing, and timing is hard --my daughter is still having accidents, when she is pulling down her paints to go! Two year olds are busy, so they get easily distracted.
When your daughter has an accident, just tell her "pee goes in the potty," and take her off to the potty. Also, stop changing her on a table, etc. Do everything in the bathroom.