My suggestion is to borrow or buy a previous edition.
Tbh I used Tim Dixon's book and I didn't exactly find his stats helpful. Usually when they publish the textbook, they base the stats from the previous year. You will need to do current statistics research by yourself throughout the HSC. If you want to stay on top, the best thing is to read the news and be aware of economic conditions domestically and internationally, it really helps with understanding the syllabus and theory.
Sources of economic updates etc:
1. smh.com.au - Ross Gittins the economics editor, he publishes articles once or twice a week on present economic issues, he has a blog too
SMH is also good for keeping up with media releases such as interest rates and unemployment rate trends
2. rba.gov.au - really good for reading about interest rates and possibly u/e, they elaborate on their policy stances
3. abs.gov.au - mainly stats and has graphs
tl;dr: buy an old edition of the textbook, theory will generally be the same, just stats are outdated.. but then again in HSC economics, if you want to be stand out against other students, you can study those old stats because they inform you of Australia's economic history and trends and input that in your essays
all the best! you will enjoy the subject.