The next Golden "Lucky Draw" figure is the Voyager Optimus & Trailer (which was released in Japan - it's different to the Deluxe Trailer released here), and a store in Singapore appears to have one to give away. Entry is to their customers who spend at least $100, until October 2012.

Perhaps there are more of them, like there was for the second movie, which saw one being given away by Myer here (as one of 88 produced - not sure where most of those other 88 went to though).