I think that you should be extending the ICO to after November, the market is not at a great condition at the moment, because of the upcoming forks, people will be afraid to invest at the ICO because they want to keep their bitcoins so they will be able to receive the new coins and tokens.
It's litteraly a gamble to start an ICO on such conditions, and I think that even an ICO that deserves to be successful can end up being unsuccessful just because the timing was bad.
It's not a good idea to extend the ICO just because the market is in the doldrums.
If there is any major event (good event) and the extension of the time period to be ok.
Unsolicited extension of ICO time to existing participants and interested participants will be a heavy blow