If money is an issue, aren't you better off sticking with the bike you have? Sure, it's a road tourer, but it should still be OK on gravel or dirt roads. I think you can get 35-38mm tyres to fit on a 520. You could start of on your 520, see how much weight you end up carrying, test ride the above bike in the UK or Germany, and decide once over there which you like better. While in Qld try a bit of off road riding on your current bike - see how it goes.