At the end of The Book of Eli,
Eli and Solara reach Alcatraz, Eli recites the book, and he dies. To avoid spoilers in the title of the question, I'm calling the period from when Eli reached the island until Solara left for home the "end period" of the movie. I think one week is a hard lower limit for just reciting the book, assuming a normal speaking rate, eight hours a day for doing normal human things other than reciting text, and an upper limit of eight hundred thousand words in the book. But Solara could have stayed on the island much longer and Eli could have survived the bullet wound and died later for another reason.
How long was this "end period"? Evidence from the film or from the screenplay/story author would be an acceptable basis for an answer.