Afternoon au pair

Looking for someone to work as an au pair 5 days a week from 16:30 to 21:30. The family has two boys, aged 3 and 6, they go to a british school so they understand english. We live near plaza de Cataluña (Principe de Vergara).
The work will be just taking care of the children: play, park, homework (basically reading), bath, dinner (that will be already cooked or very simple to make such as pizza, omelette, salad) and putting them to bed. No laundry, cleaning or so required. 
We would appreciate someone happy that enjoys being with children, specially very active children as mine are, who would like to play with them, cook with them, ride bikes...