This will be a great and rewarding experience for you and your family. As a former student coordinator for a Scandinavian exchange service I placed many students in our area for a school year. Almost all of the students and families had a great and rewarding experience.
Our family has hosted 2 Sweedish girls for a school year as wells as 2 Russians and one Costa Ricaian for 2 week periods. The Sweedish girls spoke excellent English as they take English startng in 3rd grade.
My best advice for you is keep your girl busy. Take her to as many places as you can and let her experience as much of America and our culutre. I live a small town of about 300 so we also had a 45 minute drive to a mall. As time went on doing things at school and with their friends was more imporant that shopping at the mall...especially since we were behind Eurpoe in fashion. (At least our local mall was.)
Good luck :)