Hi antho13ny,
I disagree. If the OP wants to learn some extra topics in preparation, there's nothing wrong with that. It may be true that 'many' people can take it without prior preparation, but some need it.
I would agree with this statement for every other subject except for Further, but I don't totally disagree with it. Now that's not to say you shouldn't skim over some of the information, but, in my honest opinion it isn't worth studying ahead in this subject. I see that you are already doing Methods, so luckily for you, if your school picks Matrices, Graphs and Relations and/or Trigonometry, you would have already covered about 80-90% of each of these courses by the time you get to year 12.
Now my main issue with studying Further Maths in advanced is that this is the subject with probably the least learnable content and by the time that you reach year 12, you'll have forgotten the content or at least need to revisit it anyway. It's also very important to note, that you have about 1 term of revision between the completion of your final topic and the final exams indicating, firstly, how little content there is and, secondly, the amount of class time you'll have to revise is sufficient, if used wisely.
If you insist on studying ahead, I'd go with what Aaron has suggested and look at the 2 topics for the core as it is probably the least familiar to you at the moment. However, the best preparation, in my opinion, familiarising yourself with your CAS to death. When you reach a point where the only mistakes you're making are not because of misunderstanding but rather because of silly mistakes, it becomes a matter of perfectionism, which I would suggest is the difference between a 45 and a 50. Learn to input numbers quickly and accurately onto your calculator, play around with the geometry application, with the defining function, with the statistics page, and the spreadsheet. Learn to solve problems 2-3 different ways, so that when you get around to checking your answers, you can confirm them using a different method on your calculator (especially considering that you get it for every single SAC and exam). Also, learn to read questions properly, the easiest mistake to make in any Maths (and particularly) subject is misreading the question, start practicing on your maths tests now.
Basically, my point is, don't stress about the content. Instead work on slowly developing the skills you'll need in Further to eventually attain perfection.
Understandably, my way of approaching things isn't going to work for everyone, so do what suits you in the end.