QQ w/ a wierd river decision

[stu-unger]

villain is a complete donk, he is super loose pf and pretty much the same goes for post flop. i have seem him get aggro w/ good hands, but hes the normal call down w/ tp or an underpair kinda guy.

50nl 3 handed (table just went short last hand)
effective stack 55
dealt to hero Q [img]/images/graemlins/club.gif[/img]Q [img]/images/graemlins/diamond.gif[/img] in SB

pf- button calls .5, hero raises to 2.5, BB calls 2, button calls 2.

flop (7.5)-J [img]/images/graemlins/club.gif[/img]10 [img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/diamond.gif[/img]
hero bets 6.5, BB calls, button folds.

turn (20.5)- 6 [img]/images/graemlins/heart.gif[/img]
hero bets 13, villain calls.

river (46.5)-A [img]/images/graemlins/club.gif[/img]
hero...

i think i played the river right, but im not sure whats optimal here. the pot is huge and i only have ~30 left. who blocks and who c/fs and why...