NL100: bottom set facing a river shove

[carol-ann]

NL100, 5-handed. Fishy site. Villain is unknown but given the site probably not very good. Hero probably a donk as well, at best a TAGfish (not my hand, I just got in an argument on another forum).

Hero should have bet more on the flop and turn. That being said, what do you do on the river?

UTG ($93.35)
MP ($91.90)
Hero ($95.40)
SB ($108.40)
BB ($172.55)

Preflop: Hero is Button with 5[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/spade.gif[/img].
1 fold, MP raises to $4, Hero calls $4, SB calls $3.50, 1 fold.

Flop: ($13) K[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] (3 players)
SB checks, MP checks, Hero bets $8, SB calls $8, MP folds.

Turn: ($29) 7[img]/images/graemlins/spade.gif[/img] (2 players)
SB checks, Hero bets $18, SB calls $18.

River: ($65) A[img]/images/graemlins/spade.gif[/img] (2 players)
SB bets $78.4 (All-In), Hero...?

Edit - yes it's NL100; the guy who posted it must have been confused about the games he plays lol.