Nursery schools in Pittsburgh

Hello, we're Italian and will be moving to Pittsburgh in a few months. We have two daughters, one aged 4 and one 1 and a half. We'll probably live in Mt Lebanon, and we've looked for schools on the Internet. We like the Montessori school for the elder, but we still don't find a nursery school for the little one. In Italy she stays in a nursery from 8 am till 4 pm. Can you give me any suggestion? Anyone knows the Montessori? Is it a good school? And, what is the school calendar in Pennsylvania? Thank you so much and... See you soon!!