Top Pair & Nut Flush Draw

[BPPoker]

Party $400 NL
Hero was $500+ Villain just sat down and is posting therefore has $400. No read on him.

Villian posts BB in CO
Folded to Hero in MP who limps w/ A [img]/images/graemlins/heart.gif[/img] 3 [img]/images/graemlins/heart.gif[/img]
Villain checks and SB completes, 4 to flop.

Flop: A [img]/images/graemlins/spade.gif[/img] 4 [img]/images/graemlins/heart.gif[/img] 10 [img]/images/graemlins/heart.gif[/img]

Hero bets $12 Villain raise to $45
Hero re-raises to $120 Villain calls.

Turn: 5 [img]/images/graemlins/club.gif[/img]

Hero All in for ~$400 and has Villain covered. Villain has $276 left.

Comments on the play please.

Is the "stop and go" OK here? Do I go all in on flop?

I felt like my hand+draw was too big not to re-raise with. Feedback is appreciated.