One week should do it for HTML. CSS about month, but what is good that you have many references that can be used while you are creating sites.
I learned everything by taking up the whole Web Design thing as a hobby, as you practice and practice, you get better at it, i learned HTML & CSS together and over the period of a few years I've been perfecting those, though, theres still plenty more for me to learn, 's just about practice, trial and error etc.
anyone who says they arn't still learning is a lier. Everyone needs to go back to things at a point (when theres a new version of the language maybe, or just cause they can't remember everything)