I would recommend against doing the $500+ sim prep that FlightSafety offers for ASA; in my mind it is simply too much coin to spend on a regional job, but that is ultimately for you to decide.

I interviewed there something like 2 years ago so my memory is rusty, but what they're looking for is basic instrument skills and the ability to maintain heading, altitude, airspeed, a 45 degree bank angle in steep turns, and fly an ILS. They give you a fairly comprehensive briefing prior to getting in the simulator so that you are somewhat familiar with location of things, symbology on the displays, and how the sim handles (its very sensitive on the roll axis).

Study the gouge on www.aviationinterviews.com and you should be fine. Good luck!!!