The song being sung as the dog squad search the compound is the theme from the original series Prisoner (1979)
While in solitary confinement Jacs Holt is singing the song "On the inside" by Lynne Hamilton. This is in homage to Wentworth's predecessor and it's theme song from "Prisoner".
From the details provided at the Jackson's in Something Dies (2013), it's implied the series begins in early October 2012.