Hi,
Have you tried the overnight, olive oil wrap treatment to kill the adult lice? It's an old, home style remedy, but it works! It suffocates & kills the adults. To get rid of the nits/eggs try a vinegar wrap. There's various articles online that you can research about the effectiveness of olive oil and vinegar treatments.
When I had it i used rubbing alcohol. Every 3 or 4 days. For atleast 3 or 4 weeks. That's how we got rid of both my sisters to. ( they brought it from school) dog shampoo works too! But you can only use that like once a week. then put hairspray in her hair before sending her to school. It will help prevent her from getting it back.
There's a place in my town called Lice to Know You I think, a salon that specializes in combing treatments to get people lice free. Anything like that where you live?