Call or Fold this River?

[rwdvc]

I have 200 hands on my villain and so far he is playing 25/15/2. I feel like I'm way behind on the river because it would seem his range is somewhat polarized to Ax or Kx after the flop. Even if not I might be looking at QQ which I'm behind to as well. I guess I just felt lost this whole hand. Thoughts?

Poker Stars, $0.10/$0.25 NL Hold'em Cash Game, 5 Players
LeggoPoker.com - Hand History Converter

BTN: $127.95
Hero (SB): $36.05
BB: $23.05
UTG: $28.25
CO: $22.70

Pre-Flop: J[img]/images/graemlins/spade.gif[/img] J[img]/images/graemlins/club.gif[/img] dealt to Hero (SB)
UTG folds, <font color="red">CO raises to $0.75</font>, BTN folds, <font color="red">Hero raises to $2.10</font>, BB folds, CO calls $1.35

Flop: ($4.45) K[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/heart.gif[/img] (2 Players)
Hero checks, CO checks

Turn: ($4.45) J[img]/images/graemlins/diamond.gif[/img] (2 Players)
<font color="red">Hero bets $2.80</font>, CO calls $2.80

River: ($10.05) K[img]/images/graemlins/heart.gif[/img] (2 Players)
Hero checks, <font color="red">CO bets $6</font>