The $580 price level was first support zone matching last reaction size, the market traded down to it and turned about $40 higher to $620 price level. It's continued to see selling pressure so I believe this means another lower low should form.
Next major support zone is the aforementioned $548 area that has confluence on a few different counts. 1) an open gap level 2) would make a 15% pullback in the stock that matches the approximate size of the October-November 2011 correction and 3) It matches the same size of the reaction from last week if subtracted from the last swing high at $620.
Once the reaction is complete a new bull market high for Apple stock prices should resume.