Maybe there is something I am missing here, but I cannot quite work out whether you 'feel bad' because you think your daughter is not in the best environment for improving her speech (in that she doesn't attend a Krippe) or whether you need to go out to work (whether financially, to continue your career or for your own well-being) and 'feel bad' because you can't.

If your daughter is slow to speak, I'm not sure that putting her into a group where she is likely to be confronted with different languages and accents in addition to the ones she already has to contend with is really a solution - or even a step towards one. You don't tell us whether the people she spends her time with all speak the same language. If not, it is no surprise that she is 'behind' others of her age. However, it is never a bad idea to see if there is an underlying reason (poor hearing for example).

Are you really looking for a Krippe, or would a play group (Spielgruppe) be an alternative? If you Google 'Spielgruppe Uster' there are several possibilities. Perhaps something will help you further there.