Tax implications on redrawing from current POR loan and convert to IP?

Would someone be able to give us some thoughts on the the below scenarios?
Able to recommend a tax agent to have a better understanding of possible tax implications to us?

Given / Facts:
1)      POR (Place of Residence) bought in 2008
2)      Now 20 yrs old Villa property with 2 BR, 1B, 1G & 2 covered carport spaces.
a)      With new flooring, installed inverted air-conditioning on 2 rooms and living, converted from electric to gas cooking, 2 covered carports & covered with pavers the back of the house. 
3)      Current loan amount balance of 30K.
4)      Available funds of 270K (Available for redraw since the loan account has this redraw facility) – we have placed our entire savings to our home loan to be able to pay the loan ASAP.
5)      Both my husband and I are working & with borrowing capacity (with Principal of approval of AUD1M)

Intentions:
1)      To convert the current POR to an investment property
2)      To be able to upgrade to a bigger POR

3)      To find a financial structure that will work for us that we will be able to do upgrade and start with our 1st IP.

Strategies /Ideas
Option 1 (Most referred)
a)      We are thinking of re-financing the loan and hoping to be able to take out the total available funds of AUD270K + equity & then covert to investment and pay interest only.  Therefore increasing the loan on the current POR and maximize tax benefits.
b)      Take a separate loan the prospect POR. 
Option 2
a)      We are thinking of re-financing the loan and hoping to be able to take out the total available funds of AUD270K + equity & then covert to investment to pay interest only.
b)      Don’t buy now a POR and rent for the next 1 year while looking for a POR & take another IP
Option 3 (least referred)
a)      Proceed with the upgrade and sell the POR. 

Dilemmas
1)      We do not want to mess-up with tax authorities , will someone able to give us some thoughts of the possible Tax implications & CGT Tax?
2)      If the above idea is not feasible, we proceed with the upgrade, convert to investment and sell it before 6 years.  Again, what kind of tax / CGT tax we might face that might cost us more in the future?
3)      Since both my husband and I are working, are we better to give-up the current house and start investing to new property?

Thank you in advance and hope to you from you all.