Word from Banter Toys, who are the distributor of Topps Trading Cards and Loyal Subjects in Australia...

The new Series 3 Loyal Subjects figures will arrive middle of next month, with the Limited Edition Nemesis figure already in stock. These figures can be purchased at EB Games, Kinokuniya (www.kinokuniya.com , Scifi Toys (www.scifitoys.com.au), Impact Comics (www.impactcomics.com.au), and Karrinyup News (Shop G3 Karrinyup Shopping Centre, Karrinyup WA 6018).
That should be Series 2 of Loyal Subjects, not Series 3, as the second series is on their site as coming out in July. (and there has been no mention of a third series yet)

I'd be guessing that those stores and sites would be where you can order the Nemesis Prime figure, or maybe have a limited number in stock. Best to ask them about it.