2nd pair oop on low board

[megatron]

Seem to get a little lost in these low board oop situations.

Opponent is 68/38 over 78 hands. He let's you know when he has it.

Full Tilt No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

CO ($60.65)
Button ($50.20)
SB ($96.80)
BB ($49.25)
UTG ($52.95)
Hero ($75.35)

Preflop: Hero is MP with 7[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/heart.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $2</font>, <font color="#666666">1 fold</font>, Button calls $2, <font color="#666666">2 folds</font>.

Flop: ($4.75) 9[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $3.5</font>, Button calls $3.50.

Turn: ($11.75) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $7</font>, Button calls $7.

River: ($25.75) 2[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets ????</font>,

Any thoughts on what I should be betting here, if at all. How are the flop and turn bets in this situation? A lot of nines in his range. A5, A3 as well as some low connectors. 46s not out of the equation either.

[Go_BroKe]

I would check the turn and look, what he does.