No one knows for sure, but Matt Russell the head of BMW M North America said in an interview that the E92 would be here for 2013. So at least a partial MY13 run is expected if not a full year.
Current: '13 E92 M3 Euro Delivery 9/4
Wife's: E39 M5, E36 M3, E30 M3
Gone: E86 M Coupe