wow, you have your hands full. stay strong. dont get mad at her. she is probably still angry that her mom was taken away from her, and unfortunately you are the one around the most, who gets to take the 'punishment'.
I think that some talk therapy might be good for her if she hasn't already had it, or even if she has, maybe some more could help her sort through all of her feelings.
Try to be patient, be it doesn't mean that she can get away with it either. She should be punished the same way that the other kids would be punished.
Talk to your husband, because unless you have his support and you are both working together as a team, nothing will work. Good luck!