Need advise......

My name is Sandy and I am looking for my neice born 3-9-1980 in Houston, Tx. Born at Jefferson Davis Hospital. Her name at birth was Jamie Louise Kramer. I have been searching for a long time for her and have had no luck. I have been speaking with the birth mother and she is looking too. I am the birth father's sister. The birth mother stayed at a maternity home for unwed mothers in Houston and the adoption went through Catholic Charities. Too make a long story short, the birth mother made friends with a lady that worked at the maternity home and this lady called the birth mother a few weeks after this adoption and said that the adoption did not go through and they were bringing the baby back to Catholic Charities. This lady met the birth mother at a local mall and let the birth mother see the baby for a few minutes before taking her back. I think this is called a failed adoption. Now I am back to square one and guess I need to find out from the state, which adoption agency handled the adoption?? Has anyone ever heard of this happening and what do I do next in trying to locate her?? I would appreciate any help I could get. Thanks Sandy