When we first arrived in Switzerland we were also looking for English speaking and eventually sent the children to Tiny Tots. Check out www.tinytots.ch
The fee structure etc is available on the site.
In addition if you were prepared to go bilingual check out the following site. http://www.playintheusa.org/kita/kita.htm
I am not sure on their repuation for pre school but have friends who have used them for Summer School and think they are great.
Best of luck