Holiday

Hi Sisterhood,
I'm travelling with 3 kids and myself for a holiday in Qld for over 10 days in May. Proserpine to Brisbane. Can anyone point me in the right direction for a
a) hire car which can fit 2 booster seats
b) hire car insurance
c) when is the best time to book the hire car
d) and is there any discount /coupons I could use?
I'm thinking maybe the swift or corolla. I'm needing leg room for my kids and not too worried about the boot space.