K3s. 25NL 6max. Line check/RIver question

Party Poker No-Limit Hold'em, $ Hero (3 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($51.43)
Button ($21.99)
SB ($69)

Preflop: Hero is BB with K, 3. SB posts a blind of $0.10.
Button raises to $0.5, SB (poster) calls $0.40, Hero calls $0.25.

Flop: ($1.50) 3, 6, 3 (3 players)
SB bets $2.42, Hero raises to $8.7, Button folds, SB calls $6.28.

Turn: ($18.90) 9 (2 players)
SB checks, Hero checks.

River: ($18.90) 6 (2 players)
SB bets $4.03, Hero calls $4.03.

Final Pot: $26.96

what do I do if the river bet is 10, 15, 18, 23?

I don't think the draw overbets the flop like that, and I don't think a six checks the turn. I'd call damn near anything in 6max here.

flop and turn are fine, i call anything on river not more than potsize