TT Flops the Nut Set - When Do i Drop the Hammer?

[GFunk911]

4th hand of 5/10, nine handed, no reads.

Sorry, it's goddamn Full Tilt and I lost the history.

MP raises preflop, i call TT in the cutoff, 4 players see a flop (button folds so I am the "new button").

T82r. Checked to preflop raiser who bets, I call, UTG calls

(~$75 pot) Turn is an offsuit Ace. UTG springs to life and bets, PFR raises. Do you 3-bet or flat call?