Preflop- I think this is a great spot to raise with your A4QT, but a call is fine here. My raise/call ratio usually would be 70/30 in this type of spot.
Flop- You have the 3rd nuts for high, and the 2nd nut low draw for low. Not a terrific hand, but in the .50/1.00 O8 games this is a solid hand, certainly worth of calling a lone bet.
Turn- One player is gone, the pot is now 3-handed when you make your first decision. I think this is a great spot to raise. It is very hard for a lone player to have you scooped if a low card comes. I think your hand warrants a sort of "semi-bluff" here.