It says you're sitting your HSC in 2017, and if this is the case then you've got plenty of time to improve - so don't think of it as a race against the clock and an 'improve or else-' situation. In terms of your split, here's some general advice that I stuck by (tried to at least):
S1 - it'd be good to familiarise yourself with the 'standard' sorts of questions (i.e. graphs/passages - keep practising extracting necessary information from these without making ANY assumptions, logic game style questions etc.), but also bear in mind that the actual exam has a set of questions that are often very different to these, so perhaps trying different sorts of logic puzzles/games could help.
S2 - I didn't do the best here, but the general consensus for 2 seems to be to read lots if possible and try to get a feel for what each character is feeling etc., while for practice, make sure to pay attention to detail while not taking everything in the passage at face value (also, answer explanations I found were very helpful in getting you in the right mindset and starting to get you thinking about the nuances of certain passages).
S3 - biggest thing here is practice, and lots of it. In terms of how to solve the different styles of questions, if there's one thing you remember it should be to map as often as possible - with practice you'll notice common layouts of common patterns (for example you might get quite good at spotting a pattern where a dot moves 1, then 2, then 3, then 4 spots because you've mapped out that precise pattern so many times already - BUT considering the change in style of a lot of S3 questions last year I'm not sure if this still applies, but it's definitely a good technique to practise).
In general, don't have the mindset that any UMAT practice HAS to be from a prep course or ACER etc. Anything that gets you thinking in the correct mindset will be good practice and perhaps a break from the traditional style of practice could be beneficial. Try to identify your weaknesses and work on them, and remember that improvements don't come in leaps and bounds all the time - a gradual rise in percentiles in practice exams shows you're getting the gist of things too. While your results now might look 'bad', keep in mind the workshop is touted to be extra difficult, and that people can (and often do) get very different results during different attempts. I didn't do much in the way of difficult questions last year, but I did find that the practice I did helped in jogging my memory and putting me in a good mindset for the actual exam, and that is as good as anything IMO.
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