James, I see. Then yes I'd say you have a definite flour issue and in particular a hydration issue. You really need to aim for a high protein variety, minimum 13% to get you started. It is definitely possible to make an all purpose flour based NY style, but it's not likely have the right crust texture or brown properly at normal oven temps. There are ways of improving all purpose flour by adding dairy whey, etc, but that's doing it the hard way(see the NY Lehmann style thread for more info). You also need to following the kneading and mixing instructions to a tee. Yeast, as long as its still fresh should be fine. I've not really noticed that much difference between them. At the moment I've got instant dry yeast, Lowan brand from Coles, it comes in as capped cardboard cylinder, brown label. It stores in the fridge and is very handy.
I would imagine canberra being a pain for sourcing high-protein flours. There are more than like some suppliers who carries various flours around in places like Fyshwick. Although if you only want small quantities, you may have to go with an Italian bread flour like the one Molini makes. It maxes out at 12.4% protein content. You should be able to find these Molini flours at Italian delis and continental food outlets in Canberra.
Finally, my best advice is to read the Tom Lehmann thread in the NY Style section thoroughly. Pretty much any question you might have and all recipe variations are covered there.