Setting up a company to undertake the development doesn't make sense (with the details provided) - why can't you just get an ABN & register for gst?
Total revenue: $2.7m incl gst, gst collected = 1/11 x $2.7m = $245k
GST paid (construction) = 1.05m x 1/11 = $95k
GST Payable = $150k
Gross...