How to play mraginal hand from the SB

[kerk]

THis is a hand i constantly have trouble with.

PokerStars No-Limit Hold'em Tourney, Big Blind is t50 (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

UTG+1 (t5075)
MP1 (t2725)
MP2 (t765)
MP3 (t1250)
CO (t2505)
Button (t1990)
Hero (t4770)
BB (t1880)
UTG (t4255)

Preflop: Hero is SB with 8[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img].
UTG calls t50, <font color="#666666">2 folds</font>, MP2 calls t50, MP3 calls t50, <font color="#666666">2 folds</font>, Hero ???

Its not worth raising is it? playing a marginal hand out of position. But if i limp in and an A comes on the flop how do i play?

completes, <font color="#666666">1 fold</font>.

Flop: (t250) Q[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, UTG checks, MP2 checks, <font color="#CC3333">MP3 bets t100</font>, Hero calls t100, UTG folds, MP2 calls t100.

Turn: (t550) 5[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
Hero ???