Flush appears on turn, You make top two but raised all-in..

[Haplo]

no real info on villain

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
7 players
Converter

Pre-flop: (7 players) Hero is BB with T[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">UTG raises to $1</font>, UTG+1 folds, MP1 calls, 3 folds, Hero calls.

Flop: T[img]/images/graemlins/diamond.gif[/img] 2[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/diamond.gif[/img] ($3.25, 3 players)
Hero checks, UTG checks, <font color="#cc0000">MP1 bets $0.5</font>, <font color="#cc0000">Hero raises to $4</font>, UTG folds, MP1 calls.

Turn: K[img]/images/graemlins/diamond.gif[/img] ($11.25, 2 players)
<font color="#cc0000">Hero bets $4.3</font>, <font color="#cc0000">MP1 raises all-in $11.45</font>, Hero ?????

What is my action? I check raised the flop because the preflop raise was weak, and the bet on the flop was weak as well, and I had top pair and I wanted to know where I stood.

The 50c bet on the flop could've been with a flush draw, a stronger hand that was slowplayed, or it could've been with air.

Comments here? (Do you call the all-in--we're getting close to 4 to 1, not enough to fill up, but we might already be the best (or we might not).
Thanks