Unfortunately with your record. you have zero chance of getting an international student scholarship from Australia (formerly called "IPRS" and now "Australian Government Research Training Program International Fee Offset Scholarship"). Best to be realistic about this from the get go.
Equally, I cannot think of any academic who would be likley to provide a scholarship based on your record (low second class) and no evidence of research potential. If you have a friend who did so, I think there must have been extraordinary circumstances (e.g. research publications) or else it was a very low tier university.
The only possibility you have is to get funding from Sri Lanka and then try to find a supervisor in Australia who will accept you. This funding needs to have two parts - (1) money to pay the substantial fees that Australia charges overseas students and (2) money to support you living in Australia which is not cheap even living the student life.
The reality is that you are competing with people who have evidence of research capacity. This comes usually through published papers. If you have not done any research that is publishable in the past the options are to work in the literature and produce a review paper on a topic of broad interest. This is a path that I have seen used successfully in the past. Alternatively do you volunteer in a research lab, do you have experience in research procedures that you have developed through spending time in a research lab?
Without some evidence of a capacity for research, it's hard to be at all positive about your chances of achieving your goal.
Sorry to blunt!