Nanny with fluent English

We are looking for a fair and honest nanny for our two children who are 3 and 5,5 years old. They both go to kindergarten so we need help in the afternoons: more less Mondays 5:30 - 7:30pm, Wednesdays and Fridays 3-5 pm. It would be great if our nanny could also come more often in "emergency situations" when e.g. children are ill. We require fluent English to play and communicate with our children. We believe that they are too young to have English lessons and the best way to get to know English in such age is simply to play and have fun in English. Responsibilities: playing with kids at home and in our garden, having fun, going for walks. We live in Białystok in Zawady area. We require experience in taking care of 2 children (or more) at once.