overpair against limp raise??

[lacrymosa]

is this line weak? I had no read on the guy and I dont' know why ppl would limp raise, unless they had a big hand.
Poker Stars
No Limit Holdem Ring game
Blinds: $0.05/$0.10
6 players
Converter

Pre-flop: (6 players) Hero is Button with 9[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/heart.gif[/img]
2 folds, CO calls, <font color="#cc0000">Hero raises to $0.3</font>, 2 folds, <font color="#cc0000">CO raises to $1</font>, Hero calls.

Flop: 7[img]/images/graemlins/heart.gif[/img] 5[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/club.gif[/img] ($2.15, 2 players)
<font color="#cc0000">CO bets $1.7</font>, Hero ?