Person native in english for conversation classes

I am looking for an Student who is native in english and who wants to talk with my kids in english. 

I have two kids who are 7 and 4 years old.

I just want a person native in english to talk with the 7 years old, working on the different topics of the grammar and vocabulary while talking . 45 minutes.

And the person must also play for other 45 minutes with the 4 years old, while speaking english. 

I need theese 1.5 hour classes twice a week.

The classes will be at my home in Las Rozas.

Thank you

Jorge