malaga, firstly, I would never advocate selling a PPOR. People need somewhere to live, not all Australians live to flip.
say you have $420k in cash. invest it in a blue chip (ie. TLS), this means you can buy 80769 shares even at an inflated price of $5.20. You receive 14c dividend twice a year (FULLY FRANKED), this is equal to $22,615.
btw, in regards to your property valuation, pricing in capital growth is the surest way to make a loss. Perth is possibly the most overpriced property in the world.