Having found themselves two goals behind after 20 minutes, Redknapp's men mounted a stunning comeback at Loftus Road to record their fifth home win of the season.
Austin halved the deficit with a penalty and brought his side level early in the second half from close range.
The striker completed his treble with three minutes remaining when he rose to head home Joey Barton's corner as the London club moved out of the relegation zone.
Redknapp was delighted with the effort shown from the 25-year-old - who is the top English striker in the division with 11 goals - and believes young players can learn a lot from the former Burnley man.
"When you've got Charlie in your team you've got a chance at scoring the goals," he told Sky Sports.
"I think it's a great story, for any young guy watching football, there's a lad there who struggled around the non-league for years.
"Suddenly he gets a break, he works his way up and now he's in the Premier League, it's Roy of the Rovers stuff really.
"It's fantastic for him, he's a terrific lad and you couldn't wish for it to happen to a better boy.
"He gives everything, he enjoys every minute of what he's doing and he puts everything in.
"I think lots of young kids coming into football get everything given to them and they don't put a shift in, they don't appreciate what they've got and he's a great example for anybody that if you work as hard as he does you can get there."
QPR travel to Arsenal on Boxing Day, when they will attempt to secure their first point on the road this season.
