Munich, Germany Christa Wilhelmine Schulte

Good Day, I am actually searching for my father's birth family. His adopted name was Lonnie Walden Jr. and his birth name was Olaf Hebestreit. He was born in Munich, Germany on March 7, 1961 and his adoption was finalized in 1963 to a German woman, Herta Walden (maiden name Ultsch) and an American military personnel, Lonnie Walden. I was able to get his adoption records and his birth certificate to get this information. His birth mother's name was/is Christa Wilhelmine Schulte and she was born on December 25, 1932. I know that she was divorced at the time and was working as a train conductor. I have been led to believe that my father may have had a twin sister also. I am looking for anyone that might be connected. My father passed away 5 years ago and this has always been of serious interest to me. Thank you for any help anyone can provide.