KQo OOP with bottom full house

[genya]

Poker Stars 2/4 6-max
Game is soft and somewhat passive. No read on villain.

Dealt to Hero Q[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/spade.gif[/img]
Villain: raises $2 to $4
Hero: calls $3 from SB
BB folds
(2.5BB)*** FLOP *** 4[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/diamond.gif[/img]
Hero: checks
Villain: bets $2
Hero: calls $2
(3.5BB)*** TURN *** 4[img]/images/graemlins/heart.gif[/img] K [img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/diamond.gif[/img] [A[img]/images/graemlins/club.gif[/img]]
Hero: checks
Villain: bets $4
Hero: raises $4 to $8
Villain: calls $4
(7.5BB)*** RIVER *** 4[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/club.gif[/img] [A[img]/images/graemlins/spade.gif[/img]]
Hero: bets $4
Villain: raises $4 to $8
Hero?

I put the villain on an ace b/c of the pre-flop raise, so I expected him to call the turn c/r. What is my river action? Anyone make a call here?