Small Set Faces Pot-Sized River Bet

[jjk22]

$1-$2 NLHE live in Atlantic City.

Reads: Villain playing weak tight approx 1 hour. I'm playing medium aggresive. Frequent $100 - $200 pots. Not chopping blinds, previously agreed upon.

Villain (SB) (~$180)
Hero (BB) (~$250)
UTG (~$80)
MP (~$700)
MP (~$80)
CO (~$250)
BTN ($150)

Preflop: Hero is dealt 3 [img]/images/graemlins/spade.gif[/img] 3 [img]/images/graemlins/club.gif[/img]
5 folds, SB raises to $7, BB calls $7.

Flop ($14): 3 [img]/images/graemlins/diamond.gif[/img] 8 [img]/images/graemlins/club.gif[/img] k [img]/images/graemlins/spade.gif[/img] SB checks, Hero bets $10, SB calls $10.

Turn ($34): 5 [img]/images/graemlins/spade.gif[/img] SB checks, Hero bets $40, SB calls $40.

River ($114): J [img]/images/graemlins/spade.gif[/img] SB bets (all-in) $123.

Hero?