I really liked the story.
Glad too see Ginny received help. I always felt that her obsession with Harry is wrong, and was unhappy when Rowling ended the book with them getting married.
The only problem in your story is Petunia suddenlly changing without a good reason to do it. Sorry, but her explanations don't hold water.
P.S. Why didn't you post the sequel, Redefining Hogwarts?