I'm looking for half sister and half brother

Hello I'm new at this... I'm the oldest sibling. Our mother passed away 3 years ago. Our mother was German. Father is alive as far as I know.. Where abouts unknown I'm looking for my half sister and half brother. Both sibling are biological same Mother and Father My half sister.. birth name..Amy Louise Thompson b. March 22, 1977 Hospital where she was born Lakewood General. This was an open adoption. I do have more info on my half sister. My half brother.. my mother gave him away at birth to.. Lurthan Services in Spokane. Born around late 1979 or 1980. We think 1980. He was adopted by Mormon Family. This was a close adoption I'm hoping I will find them. Thank you