Your question seems to be premised on the idea that the same Torah section ("parasha") is read on or about the same calendar date each year. This is not completely correct: rather, the sections are read in order, to a large extent irrespective of calendar date. (Not completely irrespective, but that's beyond our scope.)
Now, there are more Saturdays in a leap year than in a non-leap year. Those are accounted for by having two consecutive Torah sections read on the same week in a non-leap year which are split between two weeks in a leap year.
For any particular calendar configuration (leap year versus non-, what day of the week the year starts on, etc.), the particular Torah section for any given date (according to current practice) is determined, and is easy to find in orinted calendars or on sites like chabad.org
.