Take it slow. That is the hardest part. You'll want to see her well already, but take your time upping her rations. It's easy for starved horses to colic if they get too much of a good thing.
I hope you can post pictures of her progress. Poor baby! I read the other thread a month ago and bawled my eyes out. My husband came into the room and was very concerned for me.
I rescued one horse that was a starvation case from animal control. The first month was very touch and go. It took about a year until he looked really good. He grew into a gorgeous horse with the extra four hundred pounds he gained. He also has the sweetest temperament. It was the best horse decision I ever made.