The cars ussualy like to be in the 700-750 range. If you want to raise it some, make sure you unplug the IAC, then using the flat head screw on the top of the TB, turning it counter clockwise will raise it, then shut off the car, plug the IAC back in, and then pull the terminals to reset the ECU, or jsut unplug the ecu if you dont want to loose your present radio stations like me.

Make sure you mark where it was, this way if you screw up, you can always put it back.

To me it does sound like your idle is to low though.

Later!
Aj