I can't remember the title of this book. Maybe you can help?

A while back, I read this book (fictional story) about a young girl who was with her father driving in the middle of the night. The cover of the book had a picture of a car on it with the headlights from another car illuminating it. In the story, this girl's father dies of a heart attack while she's in the car and she is later picked up by a Cuban/Mexican family. However, they don't take her to the authorities nor help the father. They leave the car and the body. She lives in this house and can't understand their language but one of the people there is really nice (a woman). All I can remember without a doubt is that she flees and gets on a train heading to an American(?) embassy. I know my description is a tad vague but I'd like to re-read that book. It was really epic.