FTP $7.5K - AA Facing AllIn on the River

[Killingbird]

Have only played about 12 hands at this table so no real reads yet...I'm 9th in chips at this point (pays 18) with 50 remaining.

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $50/$100
9 players
Converter

Stack sizes:
UTG: $540
UTG+1: $4208
MP1: $980
Hero: $8515
MP3: $2445
CO: $6354
Button: $4850
SB: $12998
BB: $6652

Pre-flop: (9 players) Hero is MP2 with A[img]/images/graemlins/club.gif[/img] A[img]/images/graemlins/heart.gif[/img]
3 folds, <font color="#cc0000">Hero raises to $300</font>, MP3 folds, CO calls, 2 folds, BB calls.

Flop: 3[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/heart.gif[/img] Q[img]/images/graemlins/diamond.gif[/img] ($950, 3 players)
BB checks, <font color="#cc0000">Hero bets $700</font>, CO calls, BB folds.

Turn: 2[img]/images/graemlins/heart.gif[/img] ($2350, 2 players)
<font color="#cc0000">Hero bets $1500</font>, CO calls.

River: J[img]/images/graemlins/heart.gif[/img] ($5350, 2 players)
Hero checks, <font color="#cc0000">CO is all-in $3854</font>.

HERO?

also, any thoughts on other streets appreciated.