Does anyone know this book?

This is driving me crazy. I read this book five years ago and simply can not remember the title. It's a book about these girls that live in like Eastern Europe (possibly Romania but I'm not sure). I think their father dies, so they have to sell the house to their cousin. One of the sisters falls in love with a vampire. The sisters all go dancing in the woods and end up seeing all these creatures such as vampires there. I remember for sure at the end, the main character realizes that her life long love is trapped in the form of a frog. I feel like the words dancing and wood were in the title but I simply can't remember the title and I really need to find the book. Please help!