Hi marramarie-
My 1/2 sisters found me because they, like you, were so concerned when they found out there was another "one of them" out there. Since I, the adoptee, had NO information about my birth name, birth parents names, etc, they were in a much better position to make the connection. My sister contacted a search angel (Joanne Stanik who runs:
http://www.adoptiondatabase.org/) and she found me in less than 24 hours. I wish you all the luck in the world. Please keep us posted!