St Nicholas Church. You will find more information if you type ' Kosciol w Krostkowie',( Church in Krostkowa,) into Google rather than using English search terms. Sites are obviously in Polish, but you should be able to translate them.
Thank you Magdanjim for your response. Krostkowo was the village in which my ancestors were married prior to their emigrating to the U.S. back in the 1800's. We are hoping to visit Poland and Krostkowo in the near future and am looking forward to visiting the church. One of my sons and his wife visited Krostkowo a year ago and had a very good experience.