Basic Question, over pair on flop: Too aggressive or just right?

[Marcotte]

PokerRoom No-Limit Hold'em, $0.25 BB (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

saw flop|<font color="C00000">saw showdown</font>

BB ($6.05)
UTG ($5.60)
UTG+1 ($6.15)
Hero ($11.55)
MP1 ($24.75)
MP2 ($22.05)
MP3 ($55.55)
CO ($42.60)
Button ($18.80)
SB ($24.50)

Preflop: Hero is UTG+2 with J/images/graemlins/spade.gif, J/images/graemlins/heart.gif.
<font color="CC3333">UTG raises to $0.5</font>, UTG+1 folds, <font color="CC3333">Hero raises to $1</font>, MP1 folds, MP2 folds, MP3 calls $1, CO calls $1, Button folds, SB folds, BB folds, UTG calls $0.50.

Should I re-raise more?

Flop: ($4.35) 5/images/graemlins/diamond.gif, 8/images/graemlins/club.gif, 4/images/graemlins/club.gif <font color="blue">(4 players)</font>
UTG checks, <font color="CC3333">Hero bets $4</font>, MP3 folds, CO folds, UTG folds.

Final Pot: $8.35

Pot sized bet is to keep any str8 or flush draws out. Or is the board too coordinated, so I bet less (I'm sure checking isn't right).
I haven't played much NL, so I don't know exactly how to protect my hands.