Moving to Sydney for 4 months: Need Accomodation Info

Hello,

I am planning to move to Sydney with my family(wife & 2 sons..6 & 3 years old) in the first week of June for 4 months. I will be working with a organization for a research program and their office is at Castlereagh street area. Please guide me in identifying locality for accomodation. I am interested in renting a appartment as it will be cheaper. I would like the locality which has public transporation even I dont mind if its far from my office.

Thanx