Sorry to hear of this Soren. I'm seldomly, unlike Chris here, in areas of L.A. where runaways would normally be found, such as Hollywood, so I'm sorry but I doubt I'd be of much service to you.
But good luck man. Here's to the hope that she'll soon realize that getting a good education beats "becoming famous" hands down, and will soon return to her home where people really care about her.
If you find a particular agency that might specialize in locating runaways(I attempted a google, but couldn't find one myself), and you need me to contact them for you, just let me know.