Stay clear of this one - asw.org.pl/en/index-1.html - I've heard from several people that it's run by people who don't have the authority to run such a place (they have Polish people with papers, but no real decision-making powers to satisfy the powers that be).
Anyway, my thoughts. Most places hire just about anyone who fits, and it's rare to find a native speaker of the language working in one. If you do find one with native speakers, the chances are that they aren't qualified to teach in Poland.
You'd be far better putting the children into a very good Polish-only day care facility.