I sympathise totally with your situation, and you must have your daughter's welfare at heart to have posted as you have.
My advice would be to bite the bullet, bring her back with you, and start as you mean to go on, with a firm but loving approach to her.
You will find she will adjust far quicker than she - or you - think, and if you provide enough security at home, she will settle and loose most of the 'attitude'.
Growing up is hard at any age, especially in the situation, and your daughter's insecurity needs to be stopped, and her self-esteem mended, and your careing for her made obvious to her.
I wouldn't panic too much about her re-taking a year at this age - being secure at home with her mum who loves her is what she needs right now - the rest will fall into place.
You will get through this - promise. Be strong.
Thinking of you.