How bad is this blind defend on the flop?

[thesharpie]

Absolute Poker 1/2 Hold'em (9 handed) converter

Preflop: Hero is BB with 5[img]/images/graemlins/diamond.gif[/img], 5[img]/images/graemlins/club.gif[/img].
<font color="#666666">4 folds</font>, <font color="#CC3333">MP3 raises</font>, <font color="#666666">3 folds</font>, Hero calls.

Flop: (4.50 SB) T[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">MP3 bets</font>, <font color="#CC3333">Hero raises</font>...

Planning to bet a non broadway turn, fold to a 3 bet.

Check fold until I have a read or the board isn't as crappy for me?

How would you play A7 here if you had no real read apart from the table is steal happy and mostly weak tight postflop?