VISA please help! American in Florence for 1 year

Hello Expats, I live in America. I have the opportunity to follow my dream and move to Florence Italy. I would be volunteering as an au pair for one year. Is there anyway to have an extended visa without being a student or applying for citizenship? I know I could overstay my travelling visa, but then I would not be able to leave the country. What have you done in this scenario? I have heard of people travelling for over 9 months... what is the trick? Where is the loophole that I don't know about? Any current and factual information will help! As well as your advice. Look forward to meeting you in Florence!
Ciao! - Jordana A