$109 Party Hand - All-in here?

Okay, I know that I made a mistake by not betting the flop. Will someone take a look at the rest, though, and let me know what you think? Results in white at the bottom...

Thanks,

BM

NL Texas Hold'em $100 Buy-in + $9 Entry Fee Level:4 Blinds(50/100)
Seat 9 is the button
Total number of players : 7
Seat 2: Hero ( $645 )
Seat 8: S ( $1145 )
Seat 10: I ( $1095 )
Seat 4: R ( $975 )
Seat 6: A ( $915 )
Seat 3: R2 ( $4415 )
Seat 9: J ( $810 )
Trny:15830632 Level:4
Blinds(50/100)
** Dealing down cards **
Dealt to Hero [ Ks 8h ]
R2 folds.
R folds.
A calls [100].
S folds.
J folds.
I folds.
Hero checks.
** Dealing Flop ** [ 5h, 7h, 8d ]
Hero checks.
A checks.
** Dealing Turn ** [ 2c ]
Hero bets [250].
A will be using his time bank for this hand.
A calls [250].
** Dealing River ** [ Ad ]
Hero checks.
A bets [300].
Hero is all-In [295]
<font color="white">
A shows [ Ac, 4d ] a pair of aces.
Hero shows [ Ks, 8h ] a pair of eights.
A wins 5 chips from side pot #1 with a pair of aces.
A wins 1340 chips from the main pot with a pair of aces.
Hero finished in seventh place.
Hero has left the table.
</font>