NL100: blind battle flopped aces up line check

[pureCra2z]

SB is 20/11/1 over 150 raked hands

flop check ok?
what to do on river?

Full Tilt Poker, $0.50/$1 NL Hold'em Cash Game, 9 Players
LeggoPoker.com - Hand History Converter

BTN: $62.85
SB: $79.90
Hero (BB): $117.75
UTG: $145.85
UTG+1: $37.30
UTG+2: $83.15
MP1: $33.70
MP2: $108.35
CO: $66.20

Pre-Flop: T[img]/images/graemlins/club.gif[/img] A[img]/images/graemlins/spade.gif[/img] dealt to Hero (BB)
7 folds, <font color="red">SB raises to $4</font>, <font color="red">Hero raises to $11</font>, SB calls $7

Flop: ($22) 7[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/spade.gif[/img] (2 Players)
SB checks, Hero checks

Turn: ($22) 2[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">SB bets $13</font>, Hero calls $13

River: ($48) J[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">SB bets $31</font>, Hero ???