Overpair raised on the flop. NL10

[ckj]

Villain is an 18/14/6 tag with 65 hands.
Don't really have any notes on his play, but he has shown down twice, with top pair or better. The first hand was /w AA and it he shoved ($6 more) when the first player led out for $3 into a $3 pot. It was a 5d6d7h flop.

I was afraid of a set here, but wasn't really sure what to do.

Full Tilt Poker $0.05/$0.10 No Limit Hold'em - 4 players
Hand Converter Tool from DeucesCracked.com

Button: $10.00
SB: $15.10
BB: $17.35
CO: $10.55

Preflop: Hero is Button with K[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/heart.gif[/img]
CO folds, <font color="#FF0000">Hero raises to $0.35</font>, SB folds, BB calls $0.25.

Flop: ($0.75) 4[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#FF0000">Hero bets $0.50</font>, <font color="#FF0000">BB raises to $2</font>, Hero ?