In my opinion, Tim Riley is a good textbook but it has a lot of bs that is unnecessary. But, nevertheless it has updated stats, and uses a lot of diagrams to illustrate theories - so Tim Riley would be my pick, but you just have to be wary because Riley has a tendency drag on .
Also, in order to achieve a Band 6 in Eco, I think you need to be aware of past & current events as that is what the markers look for in the HSC. For example, if you got a short answer on globalisation's effect on financial flows (worth 5 marks), to maximize your chance of getting those marks you would have examples which would illustrate your argument i.e. positive effect = greater FDI flows can be used to finance domestic investment (China), and negative effect = speculator behaviour can create sig. volatility (East Asian Financial Crisis in 1997 and in Argentina in 2002)
So, basically what I am saying is to use Riley's and Dixon's textbook to clear concepts, and then keep yourself updated on past & recent events, and you will be well on your way to a Band 6.