50NL - River check raise size

[shoxbb6]

Villain sat down an orbit or two ago, only thing of note is that in the hand before, villain openlimped utg then folded to my raise from the bb.

Full Tilt Poker - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 6 Players - (LegoPoker HH Converter)

Hero (SB): $51.00
BB: $49.50
UTG: $87.00
MP: $53.05
CO: $50.00
BTN: $117.70

Preflop: Hero is dealt T[img]/images/graemlins/spade.gif[/img] A[img]/images/graemlins/spade.gif[/img] (6 Players)
4 folds, <font color="red">Hero raises to $1.50</font>, BB calls $1.00

Flop: ($3) T[img]/images/graemlins/diamond.gif[/img] 3[img]/images/graemlins/spade.gif[/img] Q[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">Hero bets $2.00</font>, BB calls $2.00

Turn: ($7) 5[img]/images/graemlins/spade.gif[/img] (2 Players)
Hero checks, <font color="red">BB bets $4.50</font>, Hero calls $4.50

River: ($16) T[img]/images/graemlins/club.gif[/img] (2 Players)
Hero checks, <font color="red">BB bets $9.00</font>, <font color="red">Hero raises to ??</font>

Ai or raise smaller for value?