English Teacher for Kids

We are looking for a native english-american teacher to spend time with and teach the language to our three kids aged 12,10 and 6, from 2,30pm to 7,30 pm Mon to Thu.
The idea is to pick up the kids from school and spend with them the afternoon one at the time giving english classes. We need the teacher from the second week of Sep till the end of June. We pay up to 650 Euros per month.