The Apple Media Event was held on September 12th (now I get why it was not a Tuesday, because that would have been 9/11) and only used for the iPhone, iPods and iOS.
If or when Apple holds another media event is unknown, some think it will be in October, some think it will be in November.
Some think a new redesigned iMac will appear this year, some think it will not.
A new display is probably not high on Apple's list for media events, it will probably just get a spec update (USB 3.0).