400NL - second barrel in rr pot ?

[Mat]

Villain is 20/17/3 over 1k hands, good reg. He's pretty aggressive and has 3-bet me at least 5 times this session. I have 4-bet him 2 times and he folded both, otherwise we don't have tangled much postflop. Here comes this hand :

Everest Poker No-Limit Hold'em, $2.00/$4.00 (HH Converter by Kreatief)

CO (533.04)
Button (394.00)
SB (404.00)
BB (243.90)
MP2 (301.20)
MP3 (557.80)

Preflop: Hero is MP3 with K[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img]
<font color="#666666">1 folds</font>, <font color="#CC3333">Hero raises to $14.00</font>, <font color="#666666">1 folds</font>, <font color="#CC3333">Button raises to $48.00</font>, <font color="#666666">2 folds</font>, Hero calls $34.00,

Flop: 5[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/heart.gif[/img] ( $102 )
Hero checks, Button checks,

Turn: 3[img]/images/graemlins/diamond.gif[/img] ( $102 )
<font color="#CC3333">Hero bets $65.00</font>, Button calls $65.00,

River: Q[img]/images/graemlins/club.gif[/img] ( $232 )
Hero ?

1) I guess it would have been better to 4-bet pre regarding the history ?
2) Do you think a 2nd barrel on this river can be good or do you c/f 100% of the time ? And if you bet, how much ?