call/bet/overbet with flopped nuts

Villain is 60/20. Pretty sucky. No big hands with him, none of them fancy reads.

UB .10/.25 NL

Villain is at seat 0 with $38.25.
Hero is at seat 1 with $24.65.

Villain posts the big blind of $.25.

Hero has 6[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/spade.gif[/img] UTG.

Pre-flop:
Hero calls. 66cash calls. ELVISIMO calls.
TeKnEeKz30 calls. Villain checks.

Flop (board: 5[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img]):
TeKnEeKz30 checks. Villain bets $1.25. Hero
calls. 3 folds.
Turn (board: 5[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/heart.gif[/img]):

Villain checks. dustbustr bets $2.50. Villain
calls.

River (board: 5[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/club.gif[/img]):

Villain checks. Hero goes all-in for $20.65?

Edit: removed Villain's action, sorry
Edit2: OK, so I know that this forum advocates the fast play. However I have the nuts here minus a SF draw to two outs, and I don't want to scare away the flush draws. I think the river looks like a missed flush draw. (Villain commented this in chat as well).

This push doesn't do anything. Value bet your hand.