Yes there are quite a few around. Although I am unsure how many are in Aus.
Yuo can start by looking at the garage section of this forum.
Then filter by make "Volkswagen"
I also spotted this on Ebay: http://www.ebay.com.au/itm/Electric-Vehicle-Conversion-Kit-for-VW-Frame-/200369951280
I am not necessarily recommending this but it is an option. Probably do your own research first.
There are all sorts of kits and adaptors suited to VW like :
Every build is unique. There are so many variables. So the results will vary widely and wildly. You can convert a car and make it go like a golf kart or you can convert the same car and make it go like a drag car.
But if you have limited budget you are probably going to be towards the golf kart end of the spectrum.
Batteries, controller and motor are the main / most costly components. These all have to be compatible with each other and all have to be up to the performance you are asking from them. Set your performance targets and then select a combination to achieve those targets.
Alternatively name your price.......we'll all laugh.....then we'll tell you to double it. Just kidding. But only kinda kidding. EV stuff is still expensive. Particularly if you need decent range. But then again I know people who have spent AU$20,000 on ICE engine rebuilds. So when you look at it like that EVs are not too different. Figure on around AU$1,000 per kwh assuming new batteries. Half that if you can find second hand ones. and figure on around 10km range per KWh assuming you drive like a grand parent. But don't select your battery purely on capacity. You also need to set a target number of volts and maximum current. Just for reference my pack was $2500, 7kwh, 172V and 500amps.