I agree Sanj- range is wide. But true test is only putting it up for sale and its only worth what you can get a buyer to pay. That can vary by quarter of a million at least.
RE appraisals were in mid $3m's but I am more a fan of comparable sales. Knock downs in this suburb (wollstonecraft) go for $2.5m. Real issue is lack of comparables. Turnover in this area is 1-2 houses per year.
I have found RP data not too far out unless significant reno's have been performed.