Native english nanny in Aluche Madrid

We are looking for a native English nanny to work from 17:30 to 20:00 h three days per week, to take care for 3 children 2, 5 and 8 years old. We need nanny to help childrens mother while speaking with them in English. Nanny is needed from now to June 2015, so we need someone who will stay in Madrid at least until June.
Salary 260€/month fix every month from October to June. September salary will depend of starting date.
In addition, every month  we will need additional nanny hours that will be paid at 8€/hour.