Part time summer job

I am looking for a native English speaker. My son will be seven in September and I need someone who can play with him during the month of July or August. He understands English but he has to make more effort to speak it properly.  It will be for a whole month. I need someone who can come during 4 hours every day, from Monday to Friday (ideally in the mornings).
We live in a flat with beautiful parks in Guadarrama. It is far from Madrid but with direct buses from Moncloa and cercanías to Los Molinos, which is nearby. I am looking for someone calm, down to earth who loves children and knows how to have fun with them. I’m not looking for a nanny but rather for a fun teacher who feels at home and who loves playing with children and telling stories. And if you have experience with infant or early primary students too!  We are a very easy-going family and we would love to hear from you. 
800 net euro/ month + cost of transport, which I will be paying too.