AJ hand facing reraise

[authority11]

Party Poker No-Limit Hold'em, $1 BB (10 handed) converter

MP2 ($122)
MP3 ($96)
CO ($87)
Button ($92.2)
Hero ($454.55)
BB ($92.25)
UTG ($94.8)
UTG+1 ($85.05)
UTG+2 ($101.7)
MP1 :#A500AF(villain)/ ($113.5)

Preflop: Hero is SB with A[img]/images/graemlins/heart.gif[/img], J[img]/images/graemlins/heart.gif[/img].
<font color="#666666">3 folds</font>, MP1 :#A500AF(villain)/ calls $1, <font color="#666666">4 folds</font>, <font color="#CC3333">Hero raises to $2</font>, BB calls $1, MP1 :#A500AF(villain)/ calls $1.

Flop: ($6) 4[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets $4</font>, BB folds, <font color="#CC3333">villain raises to $8</font>, Hero calls $4.

Turn: ($22) Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">villain bets $20</font>, Hero ???

How did I play this and what would you guys have done on the 20 dollar bet? Results later