Away supporters can't be charged more than home supporters (for equivalent seats) and QPR are charging the same.
Rule J.9 of the Premier League Handbook 2011/12:
"A Home Club shall not charge admission prices to supporters of a Visiting Club which are higher than those charged to its own supporters for comparable accommodation and in particular concessionary rates offered to senior citizens and junior supporters shall apply to supporters of a Visiting Club."
QPR's fixtures, like ours, are divided into Categories A, B and C for ticketing purposes. Spurs is a Cat A fixture for them and for Cat A they charge ?ú55 for General Sale tickets in the upper tier of the Loftus Road End (behind the goal at the opposite end to visiting supporters).
Links:
Premier League Handbook
QPR Ticket Information