smooth or stupid?

[Diplomatdcm]

Party 10-20 6 max
I am in the BB with K [img]/images/graemlins/club.gif[/img] 8 [img]/images/graemlins/club.gif[/img]
CO and button both limp Sb completes I check.
Flop is 5 [img]/images/graemlins/club.gif[/img] Q [img]/images/graemlins/heart.gif[/img] 2 [img]/images/graemlins/club.gif[/img]
Sb checks, I check, CO bets, Button calls, Sb calls,
I raise, all call.
Turn is a 7 [img]/images/graemlins/diamond.gif[/img]
SB checks, I check, CO bets, button calls SB calls I raise,
Co calls Button and Sb fold.
how is the bet, should i just give up, is the CO too confused to fold?