I would look to see if Sony sells the VAIO SVS15123CXB or similar laptop in Australia. Pricing would be different since I believe things cost more in your country even though the difference in currency value is relatively small. http://www.newegg.com/Product/Product.aspx?Item=N82E16834127878
It has a Core i5, HD 4000, 15.5" 1920x1080 resolution screen and it is 4.42 pounds which is pretty light given it's size. If I were in the market for a laptop, that would be the one I would most likely buy even though I have a strong preference for Lenovo ThinkPads.