My husband and I have two kids in our care. Our 4-year-old niece and 5-year-old nephew. We have had them since Dec 2015. Their parents are separated. The father wants us to keep the children and does not want them returned to the mother as she has had suicide attempts, depression (doesn't take meds for it). She has neglected her kids in the past. She has struck her son in the head and left a bruise (have photos of it). She lives with me currently as she does not have anywhere to live and cannot afford a place for herself. Her income is so low that half the time she can't afford her board. She has a lot of debt. I'm down as their guardian at both their schools, Centrelink and medicare, but I wish for them to be legally ours, as we wish to move back to our hometown (without their mother) and to have both their parental rights taken away, preferably not through court, but if need be, what do I need to do under family law?