The last one is Geranium molle, the Dovesfoot Cranesbill or Dovesfoot Geranium is an annual herbaceous plant belonging to the Geraniaceae family, right?
The first one might be Echium vulgare, Vipers Bugloss, but I have no idea if it occurs in Australia.
Edited to add links http://davesgarden.com/guides/pf/showimage/169694/
This message was edited Oct 5, 2012 8:53 PM
I don't know the name unfortunately, but the first one looks identical to a yellow flowered weed in Asteraceae family that I get all over my garden.