looking for birth mother and father

I am looking for my birth mother who, I believe had the maiden name of Clifton, I was born in Lower Hutt hospital on 29.9.1958 and was adopted by max and shirlie Mitchell. This adoption was done through solicitors and not an agency. I do not have any information regarding my father but would like to know his whereabouts also. I was only 6 weeks old when I was adopted and apparently my birth mother was in the hospital the same time as shirlie mitchell. I have been told that shirlie went to school with my birth mothers sister, but dont know how true this is.