NL50 TT against unknown, river decision.

[xoom]

Party Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
6 players

Stack sizes:
Hero: $67.05
UTG+1: $56.96
CO: $10
Button: $22.32
SB: $36.45
BB: $51.63

This is my first orbit at the table and villans first hand. Comments on my play and correct river decision against unknown would be appreciated. Thanks.

Pre-flop: (6 players) Hero is UTG with T[img]/images/graemlins/diamond.gif[/img] T[img]/images/graemlins/club.gif[/img]
<font color="#cc0000">Hero raises to $2</font>, 4 folds, BB calls.

Flop: 5[img]/images/graemlins/heart.gif[/img] J[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/heart.gif[/img] ($4.25, 2 players)
BB checks, <font color="#cc0000">Hero bets $3.5</font>, BB calls.

Turn: 7[img]/images/graemlins/club.gif[/img] ($11.25, 2 players)
BB checks, Hero checks.

River: 4[img]/images/graemlins/diamond.gif[/img] ($11.25, 2 players)
<font color="#cc0000">BB bets $5</font>, Hero ?