External English speaking au-pair wanted

Hello, we are looking for an external au-pair that is a native English speaker to spend 4 weekday afternoons with two girls aged 7 and 10. 
The role consists in picking them up from the bus stop, take them to their after school activities, help them with some of their homework and overall spend time with them whilst speaking in English.
We live in the center of Madrid, near Nuevos Ministerios tube station.
Job hours are from 4.30 to 8.00, 4 days a week. No housework is involved. 
Salary is 400euros a month
Anyone interested, please call or email.
Many thanks