hey there easy rider!
A good piece of advice, to help in remembering the more complex password, is to do a phrase instead of just randomly adding in the extra requirements. this is something i do usually.
That will stick in your in your mind better as opposed to writing it on a piece of paper. i hope that helps.
also, with regards to changing your password,
You do not need to change your passwords now, As you will be prompted when everything is implemented. I would wait till you are prompted, as you would have to change it again.