help!

I REALLY would like to find my little sister, and have no idea where to start. I know she is still in the same state, and I am pretty sure about the town. Jodee is my half sister. She was taken from her mother and put into foster care because of her mother's substance abuse problems. My father is also an undesirable individual, and they both signed off their rights to her when she was adopted. The last time my brother and I got to see her we were told that as siblings we still had a right to visits and correspondence. I wrote to Jodee a couple times, and both times never received a reply. I was not sure she was in the same home, therefore did not know if I even had the right address. It has been SEVERAL years since we have had contact, but I still think of her often. She is sixteen now, and I am twenty-three. I would like her to know that she has a three year old nephew, as well as reestablish a relationship with her. If anyone knows HOW I can go about finding her, any advice would be welcome. For years I have kept my phone number listed in hopes she would try and find me. So far, no luck.....