NL50: Set in 3betted pot - how we can extract most value here?

[ranka]

PokerStars No-Limit Hold'em, $0.50 BB (7 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Reads:
Playing this hand, the villain (CO) is totally unknown, maybe 10 hands, not more.
And I running: 14/12/3.5

Donks&Stacks
UTG ($18.55)
MP1 ($49.25)
Hero ($137)
<font color="#CC3333">CO ($49.25)</font>
Button ($71.20)
SB ($47.50)
BB ($45.65)

Preflop: Hero is MP2 with 4[img]/images/graemlins/spade.gif[/img], 4[img]/images/graemlins/club.gif[/img].
UTG calls $0.50, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $2.5</font>, <font color="#CC3333">CO raises to $6.5</font>, <font color="#666666">3 folds</font>, UTG folds, Hero calls $4.

Flop: ($14.25) A[img]/images/graemlins/club.gif[/img], T[img]/images/graemlins/club.gif[/img], 4[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero ?

Questions:
1. What we do against unknown villain?
2. What we do against known villain: 14/11/3 ~ 350 hands (These was villain stats 3 hours later)