I'd give 1 month notice too. I would tell them beginning of December for the start January. Personally if one of my long term parents came to me needing an extra week or 2 to sort it out with work I would go with it. I have friends who I know need 6 weeks to change there work schedule.

And definitely don't drop your rate. If they mention it. I would say do did it this way in lieu of a price increase.