NL25 - AQ hits flop, Villain fires on Turn, Villain all-in river

[automaton_22]

This is a reasonably common situation.
No reads on Villain.

I know I can't call the river bet.
Am I against a set here?
I guess the turn call was donkish. Should I have let this go on the turn? Raised the turn? Bet more on the flop?

Your advice?

Party Poker
No Limit Holdem Ring game
Blinds: $0.10/$0.25
5 players
Converter

Stack sizes:
UTG: $38.03
Hero: $24.65
Button: $94.04
SB: $14.76
BB: $42.08

Pre-flop: (5 players) Hero is CO with Q[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/diamond.gif[/img]
UTG folds, <font color="#cc0000">Hero raises to $1</font>, 2 folds, BB calls.

Flop: 5[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/club.gif[/img] A[img]/images/graemlins/spade.gif[/img] ($2.1, 2 players)
BB checks, <font color="#cc0000">Hero bets $1.5</font>, BB calls.

Turn: 6[img]/images/graemlins/heart.gif[/img] ($5.1, 2 players)
<font color="#cc0000">BB bets $4</font>, Hero calls.

River: 3[img]/images/graemlins/diamond.gif[/img] ($13.1, 2 players)
<font color="#cc0000">BB is all-in $35.58</font>, Hero ?