How to track stolen phone?

Yesterday, my phone was stolen at crown. I looked at the shoe shop i went to and the shop istant picked up the square sofa chairs i sat on and we didn't find it. I then went to galactic circus where i filed a report that has my name, contact details and description of the phone. As i was the escalator i tried to call my phone (it had full battery) and as i went down these three stout guys stared at me (they were more giving me a funny look) when i tried to call my phone. It only accrued to me now that they might have stolen my phone. my phone is the lg KF510 imported from taiwan and im on optus prepaid. please help =]