The latter is easy: Day(DateSerial(Year(Date()), Month(Date()) + 1, 0))
Weeks is a bit ambiguous. Do you want to full weeks? At least three days to
count as a week? Any weekday counts as a week? If a month starts on Friday the
1st and ends on Sunday the 31st (e.g. August 2008) is that six weeks? What's
your definition of "the number of weeks" in other words?