5NL: pocket pair meets river overbet

[coinflip]

PokerStars No-Limit Hold'em, $0.05 BB (9 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP1 ($9.42)
Hero ($6.06)
MP3 ($8.15)
CO ($4.18)
Button ($8.61)
SB ($10.12)
BB ($8.95)
UTG ($6.15)
UTG+1 ($7.95)

Preflop: Hero is MP2 with 7[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/spade.gif[/img].
<font color="#666666">3 folds</font>, <font color="#CC3333">Hero raises to $0.2</font>, MP3 calls $0.20, <font color="#666666">2 folds</font>, SB calls $0.18, BB calls $0.15.

Flop: ($0.80) 2[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, <font color="#CC3333">BB bets $0.05</font>, <font color="#CC3333">Hero raises to $0.5</font>, MP3 folds, SB folds, BB calls $0.45.

Turn: ($1.80) 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $0.05</font>, Hero calls $0.05.

River: ($1.90) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $2.55</font>, Hero ...

BB in this hand has been unremarkable so far. I'm surprised at the number of people that called the PFR, but the flop is relatively unthreatening and I'm inclined to treat the underbet as a check. When my turn raise gets called, I decide to "check" the turn for pot control and call a reasonably sized river bet. Villain foils my plan by overbetting the river. What now?