You already received some good advice.
I think that you need to consider carefully what you want to shoot. Another decision will be what series of lesnes to you intend to purchase over the next few years: prime lens, zoom lens, or both.
The prime lenses have typically better IQ for the same price than a zoom, because a zoom lens is a compromise over the focal length range.
An all-around lens is a nice idea, but the prices are not cheap since the Pentax DA18-250mm was discontinued. A 2nd hand Tamron 18-250mm would be a nice all-around lens. (The DA18-250mm is a rebadged Tamron 18-250mm. The Tamron 18-250mm with K-mount tends to be cheaper than the DA18-250mm but the lens is basically identical.)
In terms of prime lenses, within your price range, I have the Tamron 90mm Macro, and the Voigtlander Nokton 58mm: I can recommend both and each one does match your cash flow.
Another option would be the DA40mm. The small size package of the DA40mm is very appealling and the user reviews are good. (In my case I have a Nokton 58mm and a FA31 mm, and the DA40mm would be redundant).
Since you are based in Australia, you may find that the local lens prices are pretty high and you should compare with overseas prices from reputable photo shops. In my case, I purchased 3 out my 4 lenses overseas (Adorama, B&H, Keh). With UPS freight, the prices were 30 to 45% cheaper than in Australia. Food for toughts...
Hope that the comment will assist.