don't know what edt is, but east coast of australia is gmt+10 so find out what edt is in relation to greenwich mean time, then go figure i guess. or post it up here and i'll figure it out for you =|
Depending on daylight saving time, WA is twelve hours ahead of EDT, but now it's thirteen. 4:00pm EDT = 5:00am WST = 8:00am AEST (due to NSW daylight saving).