Oh and coming from QLD you might need a new wetsuit. I use a full length 3/2 surfing wetsuit which is way too cold in Winter, for Winter sailing you'll also want booties (I also find that as I still come off lots, if I don't wear them I get cut up feet).
Doing things on the cheap I've found that my old dive wetsuit is hopeless (impossible to sail with due to lack of flexibility) and that my Ronstan sailing wetsuit boots are hopeless as they lack the dexterity for windsurfing. You seem to be able to get windsurfing specific winter wetsuits for a couple of hundred bucks. (I'm hoping my 3/2 will still get me through this winter).
Lastly, having previously owned & sailed a Hobie 18, I can honestly say windsurfing is a hell of a lot more fun than sailing beach cats!