Have her stay up and wake her up early in the morning. Dont let her nap the whole day and go shopping so it tires her out. She'll go to bed early and possibly may keep that schedule going instead of staying up late and waking up late.
I think you need to set up a timetable to dictate the time she goes to sleep. I guess she stays up late watching movies or other fun stuff, which you should cut out and start her on the routine she had before. You can also encourage her by giving her a small present whenever she goes to bed early.