Looking for my birthmother.

Im trying to find my birthmother. All i know about her is her name (Cindy Patterson) and her age i think she is 34, she had me in Portland OR. My adoptive dad said i can try to find her if i would like, but he wont help me very much. So i need other peoples help. (: He told me to write a letter to Oregon DHS, and ask to set up a meeting with her. But i dont know what i should write. Im 17 and not good at writing letters. What do i write in a letter to DHS? Please help. Thank You.