Girl born 8-4-64 in Anaconda ISO birthparents

Hello, my name is Sandra and I was born in Anaconda, MT on 8-4-64 and was adapted a few days later by a loving family in Helena. My adoptive family was living in Billings at the time. I am searching for my birthfamily to obtain information about where I come from. I was told that Sandra is a family name of my birthfamily. If you have any information that may help me in my serch, let me know. I am just getting started and don't quite know where to go yet. Thanks