If you want an Au pair, basically a young girl without experience, you have to pay lodging, food, transport, German course plus pocket $ of CHF800-1000. They only work 30 hours a week
If you are looking at a decent, experience nanny. You have to provide the above, (language course is optional in this case), plus around $600(min) pound a week. But their working hours range from 45-50 hours.
If you are looking for a native speaking Swiss to communicate in English, it is alot cheaper. Plus no housing, lodging etc is needed. "Importing" native English or Russian speakers, you basically have to pay for their language skills.
I know of nannies who are experienced and are paid almost as much as an executive in the bank. They come with excellent reference letters.
You may try imperial nannies, based in London. There are alot more but I only know this one.
A note, you have to pay for their flight ticket to fly down to Zurich / Zug for the interview.
So if you have pocket $$ like nobody business, I say go ahead and hire a nanny...
Most of us normal working class (98%) can only afford part time Swiss baby sitters..