The 65-year-old is targeting players in January who are prepared to "give everything they have got for the club" and remains confident of avoiding relegation this season
Redknapp's side head into Wednesday's match against West Brom in 19th place in the table and five points from safety, having won just one of their 18 league games this season.
Asked about QPR's battle to stay in the top flight, the 65-year-old told Sky Sports: "It's a tough one but I think we can do it. If we're clever in the window, we can get a couple in and they could make a little bit of difference to us.
"You are looking for people that are willing to take on the challenge and say 'look we are stuck down in the bottom three but we can get out of it'.
"I'll never forget winning that day at Wigan with Portsmouth and staying up. For me, that day was probably better than winning the FA Cup final, just to turn it around, and if we can do the same here it would be fantastic.
"The players I am looking to bring in want to be up for a challenge, come here and give everything they have got for the club. If we can do that we are in there with a chance."
QPR have been linked with several high-profile players ahead of the January transfer window, including Loic Remy, Yann M'Vila, Joe Cole and Frank Lampard.
Redknapp has also confirmed his interest in signing former Chelsea striker Nicolas Anelka, who is negotiating his exit from Shanghai Shenhua, but faces competition from West Ham.