How do you play this hand?

[treeofwisdom7]

Party Poker No-Limit Hold'em Tourney, Big Blind is t150 (6 handed) converter

Button (t1115)
SB (t1648)
Hero (t1930)
UTG (t820)
MP (t1762)
CO (t725)

Preflop: Hero is BB with A[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/club.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">MP raises to t375</font>, <font color="#666666">3 folds</font>, Hero calls t225.

Flop: (t825) K[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP bets t500</font>, MP folds.

Final Pot: t1325

the reason i checked here on the flop was so i could have more time to think about what villian was holding.
I thought about folding on the flop but it dawned on me that villian could have A9 and a lot more hands that i can beat here..

how would you play this hand instead.