what is the best play on the river? and how was second barrel?

Hand converted with online PokerStrategy.com hand converter:

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$0.1/$0.25 No-Limit Hold'em (6 handed)

Known players:
[tg]BU$37.06:///////;SB$26.23:///////;BB$14.59:///////;MP2$25.74:///////;MP3$25.00:///////;CO (Hero)$34.60:///////;[/tg]

Preflop: Hero is CO with A:c, K:s.
2 folds, Hero raises to $0.62, BU calls $0.62, 2 folds, BB folds.

Flop: ($1.59) 3:s, 7:d, 6:c (2 players)
Hero bets $0.90, BU calls $0.90.

Turn: ($3.39) 6:d (2 players)
Hero bets $2.00, BU calls $2.00.

River: ($7.39) A:d (2 players)
Hero bets $4.00, BU raises to $11.50, Hero folds, BU gets uncalled bet back.

Final Pot: $11.39.

his stats in 23 hands　　vpip36 pfr23 af0,4 wtsd43 w$SD33
I think my second barrel against high wtsd player was bad.
river should be check call? check fold?