The former Burnley man scored either side of half-time as Paul Lambert's side fell to their fifth straight league defeat
Austin broke the deadlock inside the opening 20 minutes as he fired in from the edge of the box after good hold-up play from Bobby Zamora.
And the former Burnley striker doubled the hosts' advantage after the break as he nipped in front of Ron Vlaar to turn in Eduardo Vargas' right-wing cross.
Vargas went close to making it 3-0, only to be denied by Brad Guzan, before Rob Green saved from Tom Cleverley as Villa fell to a fifth straight league defeat.
Green returned to replace understudy Alex McCarthy in goal for QPR, while Vargas replaced Nedum Onuoha and his compatriot Mauricio Isla reverted to right-back as the ex-Manchester City defender sat out with hamstring trouble.
An ankle injury to Alan Hutton meant a first appearance of the season for Villa right-back Matt Lowton - one of four changes made by manager Paul Lambert following their 3-0 loss to Everton.
Villa made the most impressive start, with Green doing well to get behind powerfully struck efforts from Ashley Westwood and recalled fellow midfielder Carlos Sanchez.
But QPR surged ahead against the run of play in the 16th minute when Zamora chested down for Austin to send a wonderful 20-yard effort whistling into the bottom left corner.
The QPR backline were kept busy as Christian Benteke saw a header sail narrowly wide before Green had to be sharp to deny Andreas Weimann and Yun Suk-young produced a timely 34th-minute block to deny the Austria forward.
Villa's attacking efforts continued after the interval as Benteke towered above the QPR defence to head down a 55th-minute set play for Ciaran Clark but the defender could not scramble home under pressure.
Zamora made way for Junior Hoilett in the 62nd minute and the winger lent renewed impetus to the QPR attack, clipping a curling effort against the post.
The change in momentum proved decisive as Sanchez carelessly gave away possession in the 69th minute for Vargas to charge down the right flank, Austin finishing his low cross with aplomb at the near post.
Villa's frustrations were compounded as substitute Joe Cole clumsily got in Benteke's way as a sight of goal opened up and Green produced a fine double save to extend Villa's toothless run and secure a rare clean sheet.