You are in kinda the same area as me, I am near Castlemaine. summers are harsh on vegies around here and very water needy. Too much sunlight is also an issue - it will burn or wilt your vegies quick smart on a hot windy day.
The first thing I would suggest is pick a spot for your vegie patch that has some shade or protection from midday summer sun - or as we are planning - build a shade house for your patch.
Wicking beds are quickly becoming the garden bed of choice around here - they make growing vegies easy and so water friendly!
here are some links to explain them.
wicking bed
Mairéid Sullivan
waterright australia - water crisis solutions - wastewater treatment greywater recycling
http://www.youtube.com/watch?v=35TU5...layer_embedded
You can use anything for a wicking bed if you don't want to build a raised bed. With our budget too stretched this summer we haven't built ours yet - so I am using an old bath tub, and several clam shell wading pools I stole from my son until I can wrangle the extra dosh to build a proper raised bed system.
I have grown many vegie patches over the years and this is by far the most successful garden I have ever had - and I only water once every 2 or so weeks! - even with the recent hot`weather!