When to fold/raise AA on flop/turn?

[gergery]

Party Poker $25 NL Hold'em, $0.50 BB (10 handed). Villian was a bit loose and agressive preflop, but played pretty well on flop to this point.

BB ($50)
UTG ($10.75)
UTG+1 ($24.50)
UTG+2 ($15.55)
Hero ($32)
MP2 ($25)
MP3 ($25.95)
CO ($38.95)
Button ($20.25)
SB ($19.75)

Preflop: Hero is MP1 with A/images/graemlins/spade.gif, A/images/graemlins/diamond.gif.
UTG folds, UTG+1 folds, UTG+2 folds, <font color="CC3333">Hero raises to $1.5</font>, MP2 folds, MP3 folds, CO folds, Button folds, SB calls $1.25, BB calls $1.

My last few $2 raises had just gotten folds so i lowered it slightly. mistake?

Flop: ($4.50) 4/images/graemlins/club.gif, 2/images/graemlins/club.gif, 4/images/graemlins/diamond.gif <font color="blue">(3 players)</font>
SB checks, <font color="CC3333">BB bets $3</font>, Hero calls $3, SB folds.

Raise and fold to reraise here?

Turn: ($10.50) 8/images/graemlins/club.gif <font color="blue">(2 players)</font>
<font color="CC3333">BB bets $6</font>, Hero calls $6.

Reraise? But worried about flush and 4's now.

River: ($22.50) 2/images/graemlins/spade.gif <font color="blue">(2 players)</font>
<font color="CC3333">BB bets $10</font>, Hero folds.

Am sure i was beat here.

Final Pot: $32.50

Results in white below: <font color="white">
BB doesn't show.
Outcome: BB wins $32.50. </font>