Searching for BM born 1/31/59 in Columbus Hospital

I'm searching for my birth mother and father and a brother I think is named Michael Broach. My birth mom and dad are Jeanette and Robert Broach. I was born at Columbus Hospital (catholic) in Chicago, Ill. 1/31/59. My birth name is Colleen Jeanette Broach. I believe my brother was born 2 years after I was. I have my birth certificate as well as my adoption decree. Has anyone had any luck with petitioning the court? Is there an intermediary someone can recommend? Any info would be helpful. Thanks, Sharon