A few recommendations:
1. To find a child caretaker, or "jeune fille", I'd recommend placing an ad (in English) in the classified section of 24 heures, the regional newspaper, in the section "Personnel de Maison". It's hard to find a native English speaker, but sometimes the people looking for houshold work come from parts of Asia where English is spoken to some extent (e.g. the Philippines, India) and will speak English well enough.
http://annonces.24heures.ch/emploi.aspx
2. Another resource you might find helpful is the parenting group of the Lausanne American women's club. They have lots of useful-looking links on their website, and I'm sure you'd be able to get in touch with people who could give you better advice than I can (seeing as I don't actually have kids...)
http://www.kids.awc-lausanne.org/index.html
3. Just so you know, you don't have to choose between child care and your career. It is very common for one or both parents to work part-time, ranging from 50-80% of a full work week. This way you can still earn money/advance your career/improve your CV but also spend time with your child (and as a bonus, you don't need to do all your weekday shopping between 6 and 7 pm!). Two adults working at 80% (or one at 100% and one at 50%) can still pull in a reasonable amount of money, and it also reduces your childcare costs and gives you more family time. The vast majority of working mothers I know (and a few dads as well) work part-time, in positions ranging from secretarical work, through to financial jobs and specialist doctors. I think it's something worth considering. Don't hesitate to ask your future employers, as it is really common to do this. I asked to have my job adjusted by 10% from what was advertised and this was done no problems, my boss just had to have it approved by HR.
Good luck with the move!
HeatherM