Searching for half sister born around 1973

Around 1973 My mother had a baby girl she named Dawn Marie. She gave her up for adoption a couple weeks after she was born for reasons beyond her control. My mother has passed away about a year ago. I am now searching for my half sister. Her birth name was Gerick or Gerek. I believe she was born on March 24th or 25th of 1973 or 1972. My mother's first name was Eileen. She was living in Union when she had her baby girl. Please anyone with any helpful information of how I can find my half sister please let me know. Thanks, Maria