A military mother seeks rightfull custody of her children

Upon joining the military I signed a "waiver of service" and a "general power of attorney" so that I may get divorced from an abusive, drug addict. And allowed his step-mother to stand in court for me. With these two signed documents she not only got my divorce, but she took custody of my children without my knowing or permission. Since then I have been unable to take custody of my children due to rapid deployments, I am now a year from getting out and have sustained injuries that prevent me from ever deploying, I am now in a position to have them with me. She is unwilling to give my children back to me. Please allow me the right to be a mother.