English mother-tongue babysitter in Milan

Hi, I'm looking for an english speaking babysitter (mother tongue) for my two kids, 5 and 3 years old, who should pick them up from school at 4pm and spend some time with them till 18:30, twice or three times/week. I need the baby sitting starting from may 2014. We live in Milan between Piazza della Repubblica and Central Station.

Thanks

Chiara