Babysitter - Full-time / Part-time

We are looking for a nanny for our 6-month-old to come to our home 2-3x/week, for a total of 6-9 hours. This would be somewhat of a trial position as I get back into work and we see how it goes, so there is a possibility of expanding hours in the future, but not to exceed 20 hours/week. We have a 3 and 5-year-old, as well, so occasionally we might need help with them, too, but mostly they would be in preschool.