How can I get custody of my daughter back?

On december 12th of 2011, I decided to take my daughter on the bus to visit my mom in oregon. As soon as I got down there, my mothers roommate decided to call my aunt. that night my aunt came down and took my daughter from me and is trying to claim full custody and file abandonment on me.. it has been 6 months since I have seen my baby girl.. I try to go see her but they wont let me.. I have done everything cps has told me to do.. I have housing and income... I am doing my best to not break down.. and second of all I never signed any agreements to her having custody, I never went to court for a custody hearing, And I never and will never abandon my child... Her father and I want her back as soon as possible because I am pregnant with her new sibling and would like her to be with us.. please help me...