ISO american student

We are a spanish family looking for an american student in Madrid (Pinar de Chamartín area) to spend some time playing and speaking english with our daughters (4 and 2 y.o) during the weekday afternoons (4-6 pm aprox). We will be in the house at the same time (not looking for a nanny but a friendly teacher)
We have been living in NJ until last summer and we'd like our children to keep in touch with the american english language and culture. Only US people, please. Thank you.