AOA Manzoor,
I am not sure that if you can bring your parents in immediately. What visa you are comming on?
Have you already secured a Job or will come here and search for one?
I just moved to Australia and living in Gladstone. We are only couple and what i have figured is that the running cost would be around 1-1.5 for two people which will not inlcude the renting a house. I was provided with the house by my employer. The renting in down town will cost you approximately 3K per month a minimum.
Wassalam.
Muhammad Asif Mehmud