Sell first home or hold… help please

Hello All

I have been reading this forum which is very informative and helpful.

We purchased our first property ( 2 BR apartment) in Southbank, Melbourne in 2007 lived for 8 months and than had to move to Sydney for work. Since then the apartment has been rented out as a fully furnished property. Rental is pretty decent with rent almost paying the interest cost the property has also helped me negative gear. The property has almost appreciated by $200K, the mortgage on property in $290K now

Now we are planning to buy something in Sydney close to $640K we have a deposit of $100K and we can also avail a home equity loan of $50K if need be. We plan to initially rent this property but shift in one year time and in the meanwhile sell the Melbourne property and reduce our total mortgage.

My question and dilemma is let us say we decide to continue with our Melbourne property and shift into Sydney property after a year, can we get the Valuation (and from where) done for Capital Gain purposes as on that date and avail the six year (owner occupier) period rather than paying CGT on the whole and convert the property to  investment property.

We earn $200K per year and our pretty conservative family with one kid.

Thanks in advance for your views and help.