Hi, I know that Children First (childrenfirst.ch) offer kindergarten classes in the afternoon, and I assume they are readiing and writing in English, but you would have to check. I also don't know what kind of commitment they want, either, in terms of how many days etc. But could be worth a look. They are very close to Kreuzplatz.

Depending on where you live the WAC could be a good option. I get the train out there twice a week (once for German class for me, with childcare) and once for preschool for my daughter, and by train it's ten minutes then a walk of a few minutes. But I know it all depends on timing and all the other things you have to juggle!

Kate