Marty, the movie is based on the book Marie Antoinette: The Journey by Antonia Fraser. I highly recommend reading it, maybe after seeing the movie in order to get the full story. Here's the Amazon link:
Book on Amazon
I would suggest you read the book aloud together, maybe a chapter or two a night. She could read to you while you make dinner, you could read to her as she cleans up dishes.
As someone who has worked with literacy students I don't like the carrot and stick approach. Many parents try to get their kids to read by trading privileges. The problem is reading starts to seem like a punishment or chore. Reading should be done because it's fun and interesting. You can limit her TV/Computer use, but try not to dictate how she has to use that time.
The movie has a couple of sexy scenes and fuzzy nudity, but nothing worse than what any kid would see on MTV or a Victoria's Secret ad.
Just a side note: I've used the below website to check for movie content. It's designed for families to decide if a movie is something they want their kids to see. They break the film down to the tiniest kiss, sip of whiskey, and how many times the "f" word is spoken. I found it helpful when my nieces and nephews were younger.
Family Movie Reviews