Okay, I still haven't seen Equestria Girls. But we've got resources to share anyway, because we love you. (Well, mostly, you're sharing the love with each other... like good friends do.)
Thunder Dash wrote a double piano version of Helping Twilight Win the Crown from the movie. You can listen to it in the embedded video, and you definitely should. Then check out the sheet music and find a friend to play it with you!
Thanks for sharing, Thunder Dash!