Aupair in Madrid ( Pza España area)

Hello,
we are looking for an au pair or nanny to take care of our children (10,8 and 4 years) during 4-14 August, from 08:00 to 16:00. The person will have to take care of them, help with meals and speak english with them.
We live in the center of Madrid, near Plaza de España.
Salary negotiable.
Thanks.