Hello,
I came across your message today, and I believe I can be of some help. The place you are looking for is Langendorf. The Polish name is Wielowis{sp?}. My wife and and I were there on a visit about five years ago as my great grandfather was born in Mittel Langendorf. Langendorf was what the German's called a Rittergut. Essentialy a large estate a knight received from a nobleman for services rendered. The Gut is now a fairly dilapidated large farm, with evidence of what used to be a brewery, a brickmaking facility, and large barns and sheds.
Langendorf is located in the former German Kreis Gross Wartenberg. It was an area situated on what was then the German-Polish border, and switched sides on several occasions as the borders were redrawn. Gross Wartenberg was ruled by the Count of Kurland, who left in the closing days of WW II and eventually moved to the US.
Hope this helps you a little.
By the way, my great grandfathers name was Robert Carl Post.
Regards