I agree that the MacBook Pro you're referring to - the one they sell for $1699AU - should NOT be available to consumers. It is an outright rip off. In the UK it's the £899 model - non-retina, non-SSD, last updated over 3 years ago (ie. 2012 model).
That said, tech costs more than it did in 2009. And if you do pay a bit more, you will see a colossal performance increase from your current Mac.
Even the new MacBook (not Pro) will outperform your current MacBook - especially at general tasks - and it doesn't have a single fan, it's a fraction of the size and weight and it offers a wildly better 'retina' screen.