can i get custody of my daughter, i was in prison...the mother left the child, and the maternal grandmother has been raising her

the mother left and signed a notorized letter giving my daughter to the maternal grandmother, it was signed by a judge but no court action was taken.....i want to get custody of my daughter but what does that letter mean? Also at the time my daughters mother signed over my daughter i was not legally the father, i was in prison for 3 years and filed a paternity petition and it took me 2 years to get my daughters mother to actually be present for the hearing......my issue is that the maternal grandmother has allowed my parents to see my daughter every other weekend...almost, the maternal grandmother basically lets my parents have her when its comfortable for her and when she isnt leaving to take my daughter to alaska which is where she is from......i want to stop her from leaving the state with my daughter without my permission and atleast get partial custody of my daughter.....