Unless you're always downloading movies or something, I think 6MB per day is sufficient if you're actually researching. Also, I'm not sure about this, but I think the 6MB per day accumulates over time if it is unused, then after some time it will reset.
Also, there are some computers at USYD which actually do not have this restriction at all (i.e. fully free internet and free printing) and those are often specific for a certain area of study or a lab. Alternatively, get yourself a laptop and wireless internet.
The uni computers should really be used for uni purposes most of the time. You have no idea how annoying it gets when some people sitting on the computers are just playing games and facebooking when the computer labs are packed and many people are queuing to do their assignments.