ISO sister/half-sister

I was born in 1943 to a widow whose husband and other children, except one boy, were killed in a fire. I believe that I have a sister who was either adopted, or raised by our foster family. Our half-brother only recently learned that I exist. He has welcomed me and we are eager to find our sister. He remembers being contacted by someone seeking family about 10-15 years ago. My birth name was Richard Hansborough.