Looking for half sister born in Illinois 1965-67

I am 33 years old and my mother apparently had a daughter sometime in the area of 1965-1967 in the Chicago area and she was given up for adoption. My mother would have been 20-22 at the time and was from Duluth, Minnesota. Her name was Amy Carlson (maiden). I have no info from the father other than his name was "Mike". From what I have heard my mother tried to make contact with her before she died (1997) and was denied by either the family, or by her daughter. I really want to find her and show her her new neice.