Looking for portuguese-speaking school in SP (São Paulo)

I am an American, and I will be moving to Sao Paulo shortly. I'm looking for a portuguese-speaking school where I can send my kids. I'm also wondering if anyone has any experience with throwing their kids into a school where they don't speak the language?

My kids speak only English, although they've been taking Spanish for a couple of years. They are in 9th, 7th, and 4th grade. They've gone to international schools before and are well-travelled.

My office will be in Chácara Santo Antônio, so I'm looking for a school close to there.

Thanks.