Baby flush, how is this line? ($25NL)

Opp is 35/17/6.0. How is this line? Should I have bet the river a bit harder?

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.10/$0.25
9 players
Converter

Stack sizes:
UTG: $8.30
UTG+1: $47
MP1: $51.30
MP2: $26.90
MP3: $17.95
CO: $19.15
Button: $18.15
SB: $45.30
Hero: $25.25

Pre-flop: (9 players) Hero is BB with 3 8
6 folds, Button calls, SB folds, Hero checks.

Flop: 5 J 7 ($0.6, 2 players)
Hero checks, Button bets $0.5, Hero calls.

Turn: Q ($1.6, 2 players)
Hero bets $1.2, Button calls.

River: 2 ($4, 2 players)
Hero bets $2.5

I think it's fine. $3.50 on the river would be fine too. Against a guy this aggro you could go for a river c/r too, but it's risky.

Thanks for the feedback. I think I need to learn to bet the river (and all streets) a bit harder. In SNGs I usually bet 1/2-2/3 pot, seems that with bigger stacks 3/4 to full pot is better.