I totally sympathise with you! reading your post reminded me how my son used to terrorize me with his tantrums and sassy answers couple of years ago!I had tried each and every option available to tame him down but it was of no use!Then I took him to a pyschologist who suggested that I put him in a day care or any similar facility where he can interact with other children of his age.So I admitted him to a preschool and since then he has calm down a lot.So I suggest that you try admitting your daughter to some preschool or daycare,I am sure it will be helpful!