25nl KKs 3bet gets called... ace on flop... what do you do?

[wems]

Full Tilt No-Limit Hold'em, $0.25 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

CO ($21.45)
Button ($37.30)
SB ($11.50)
Hero ($43.95)
UTG ($79.25)
MP ($24.40)

Preflop: Hero is BB with K, K.
[color=#666666]1 fold</font>, [color=#CC3333]MP raises to $1</font>, CO calls $1, [color=#666666]2 folds</font>, [color=#CC3333]Hero raises to $4.35</font>, MP folds, CO calls $3.10.

Flop: ($9.55) A, 7, 5 [color=#0000FF](2 players)</font>
Hero checks, [color=#CC3333]CO bets $3.5</font>, Hero ???

Turn: ($16.55) 2 [color=#0000FF](2 players)</font>

Im guessing I should lead on the flop. or maybe have raised to 5$ preflop. what would you put villian on? hes 46/6.7 after ~15 hands

[DaycareInferno]

i would just lead the flop and then give up. the pot is too big to c/c, but a lot of villain's range isn't liking that flop either, so its best to get some money in there first i think.