OP, I don't think you will have any problem finding a nanny with a 55k package. As a previous nanny I looked at the overall package. I know I wanted to take home a minimum of $600-700 a week after taxes and didn't want to work over 60 hours a week. I was easily able to find positions that financially met this criteria (and this was 5+ years ago).

For what you are looking for I would say you are looking at paying 50k a year in childcare expenses, plus health insurance to make it competitive.

60 hours is a lot. Get a live-in and expect to pay a lot.