Under Investor Alley is an entire thread on Australian Investing. I would read all of it. Yes, it’s long, might take you a week or two, read it all. I also got the Barefoot Investors book, it’s good mostly because it gives the Australian perspective of what to invest in. Also, read MMM’s most popular articles. Try to read as much as you can from him.
You don’t need St George, you can invest directly into Vanguard Australia. As for which product, call them to discuss. I use the aggressive life strategy product.
The best way to start is to work backwards. What do you expect your expenses to be in retirement? Times that by 25. You’re starting late and don’t have much in savings or your super. That’s not fatal per se, but it will take a lot from you and your family. Definitely do a case study. 5 years may not be realistic, but 10 years may be. That’s still retiring earlier than most.