Top pair good kicker against an unkown

It was my first orbit and the table was looking pretty loose agressive to me. Just by waiting for the blinds, I noticed that villain capped a turn with a low pair and a K high flush draw against 4 other guys. That's the only read I have on him. So, here goes:

PokerRoom 0.25/0.50 Hold'em (10 handed) converter

Preflop: Hero is SB with Q[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/heart.gif[/img], CO posts a blind of $0.25.
<font color="#666666">1 fold</font>, UTG+1 calls, <font color="#666666">1 fold</font>, MP1 calls, MP2 calls, MP3 calls, CO (poster) checks, <font color="#666666">1 fold</font>, Hero completes, BB checks.

Flop: (6 SB) 2[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(7 players)</font>
<font color="#CC3333">Hero bets</font>, BB folds, UTG+1 folds, MP1 folds, MP2 folds, <font color="#CC3333">MP3 raises</font>, folds, <font color="#CC3333">Hero 3-bets</font>, <font color="#CC3333">MP3 caps</font>.

Turn: (6.50 BB) J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP3 bets</font>, Hero calls.

River: (7.50 BB) T[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP3 bets</font>, Hero calls.

Final Pot: 8.50 BB

What do you think? I felt I had no other option on the flop but to 3-bet him, but I got kindda scared when he capped.