diecezjaplocka.pl/index.php?akcja=spis_wyswietlParafie&p_id=357
This is a site of parish to witch belongs Budy Mdzewskie. They have books of baptism, marriage, and deaths certificate dating back to the end of XIXc. You should start your searching from there.
Earlier books were probably taken to Warsaw, because of consolidation of archives in the beginning of XXc. Bad news is that during WWII Germans intentionaly destroied polish archives and libraries (including National Library in Warsaw in 1944).
Good luck Barbaro
Michal Pontus was born in Ostrow
Unfortunately their parish have books dating back to 1905.