I am very happy to have seen your quest (by chance actually). I joined the WAC less than a year ago, my 2.5 year old goes to preschool, and I take my ten months old to playgroup there. We live in uster. And I also work at the WAC by the way!
I really love the WAC for all the opporunities that exist for my kids and myself. I have made so many friends, and it has helped me feel 'at home' in uster. I also enjoy living in uster very much. We lived in zurich before, but uster is a much better choice for children. The town itself has everything you might need, and I only seldom go to zurich for shopping or restaurant etc...
The WAC has two playgroups for the age of your daughter, and the preschool is for ages 2 and above (all in English). We have swimming and music. The playgroup you mentioned is also great for the integration into the Swiss society. For moms (and also dads sometimes) we have regular activities but also special events, like potluck dinners, cooking classes etc...we also have a library with a great choice of books and movies for adults and kids.
I could write two more pages...but to keep it short
go for uster, you won't regret it! Hope to meet you soon there, I'll send you my private email by pm if you need any help. Also you can visit our Facebook page: the WAC.