long heads up battle - had seen very few of villians hands (picked up a lot of pots, had fought from 1500 chips with 5 to play to this point)

am i too short here to fold this? obviously the turn is probably not a great card for me if opp has ace like i read... but do i have to call/push?

PokerStars No-Limit Hold'em Tourney, Big Blind is t600 (2 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

BB (t7060)
Hero (t6440)

Preflop: Hero is Button with K, 7.
Hero raises to t1500, BB calls t900.

Flop: (t2450) A, 6, 3 (2 players)
BB checks, Hero bets t2000, BB calls t2000.

Turn: (t6450) K (2 players)
Villian bets 1800 - Hero ??