how much to have built?

My neighbours and I would like to build matching and joined one car garages. I have seen several in our area that I really like, which have a loft or storage space above.
The only plan I have been able to find is American and therefore all in inches and feet, which means nothing to me.
http://details.coolhouseplans.com/de...ID=48&sid=chp2
Can somebody give me an idea of costs and what council approvals will be likely required to replace our existing garages (which have asbestos roofing) and if you know of a builder / plan readily available in Australia.
Thanks for all your help as we have never built anything before and this is the beginning of our renovation extension plans.