Thats a good idea if you need some quick $$.
But only if you are confident you will do well in TAFE.
After you complete your certificate, you may also be eligible for Advanced Standing (Academic Credit) for the subjects you did at TAFE, so you won't have to repeat the subjects you've already done, thus saving you money on those uni subjects. (this could speed up your degree by around half a year).
But make sure the course you are doing at TAFE is simlar to that of your degree at Uni, so that you can claim Advanced Standing when you start Uni. You can call UWS up and ask them which specific course would be good to study at TAFE to get the most out of your time. - since they have so many students that have done this, that they should have a list of what subjects at TAFE are equivalent to the subjects at Uni.