One of the great challenges in paleontology is having the time to go hunting for fossils. Another is having the time to figure out what you have found! Of course, I should probably add in money to do both. You are lucky to have the time and reason to go exploring. You can let others do the comparison with museum specimens and trawling through old literature to make sure no one described the species in an old obscure publication somewhere. There certainly are many areas of Australia which remain unexplored for fossils. With some of the oldest rocks on earth, there is the potential to find many interesting fossils here. We certainly have a wealth of ancient stromatolites, which you have also found. It will be interesting to see what you turn up in the future, as long as you stay away from those swimming handbags...