searching for adopted sister

we are looking for Rita Gene Holbrook born to Irene elisabeth Holbrook, born on 2-07-1943 in denver at the salvation army on jasmin street and adopted in seradon wyoming the case worker was ms. fleming my name is Tim bird and she would be my step mother's sister. her name is Beverly Clegg Bird. If you have any ideas, all this is new to me. I am a novice at searching for adopted people. Tim