Please help me with this one:

The story is set in our world and a fantasy world. The main character – a woman from our world – is being hit by a car in the first page of the book and lies in a coma throughout the whole story. In her unconscious state she visits the fantasy world. One comes to understand that she’s from a white-trash background and that she fled from her parent’s trailer as a teenager to get away from her brother who sexually abused her. She left a younger sister, (Charlene?) behind.

A parallel story is about this younger sister and her friend who gradually understands about the fantasy world where they visit in dreams (in the shape of wolfs?) and feeds on the blood of unicorns; the blood makes them stronger, but killing the unicorns sets the balance out of order and other inhabitants of the fantasy world decides to stop them. As the story unravels we understand that the woman in coma was hit by a car driven by her own baby sister who hates her for abandoning the home. When the older sister left, the abusive brother began to take interest in the younger sister…

This is perhaps not a classical fantasy story, but I took it from the fantasy shelf of a public library in Sweden a couple of years ago and found it both well written and touching. I’m now living in Belgium and I’m unable to go back to find the book, but I sure would like to know the author and the title.