Rankin Family Where Do I Belong

Hi I am trying to trace my family's geneology. My Dad Terry John Paul Rankin Born Oct 1945 died when I was 9 in 1990. I am pretty sure he originated in Geelong, Victoria, Australia and I know he went to school there. I have never been given much info and would now like to find a little out about my families history. My grandfather was Don Rankin (dec 200?), My grandmother was Ivy Marney dec 196? and my uncle was Brian Ewan Rankin Died Age 18 196?.