CGT on sale of land

I just have a couple of questions regarding CGT on the sale of land. I intend to sell a block of land I have had for over a year. When I sell the block can I add expenses such as land and water rates and interest onto the purchase price thus reducing the taxable profit? Also after searching through the forums I have come across the issue of GST. Will I have to pay any GST if I sell the land? I am in WA. Thanks you.