请教语法网的专家：

Once a woman came to Mahatma Gandhi, known as the father of the Indian Independence Movement.

She asked Gandhi to persuade her son to give up eating sugar, which she thought was bad for his body.

Gandhi asked the woman to bring the boy back in a week. Exactly one week later the woman returned, an Gandhi

said to the boy, "Please give up eating sugar." The boy agreed willingly.

上面文章中，Gandhi asked the woman to bring the boy back in a week. 这是间接引语，

直接引语应该是：Gandhi said " Please bring him in a week"

（这个直接引语我能理解in a week是一星期后！），但是，

1）改成间接引语为什么仍然是in a week, 而不是a week later,即应该是Gandhi asked the woman to bring the boy back a week later, 对吗？

2）Gandhi asked the woman to bring the boy back in a week. - 假设原文中这句话是正确的，那么这里的in a week - 一星期之内？一星期之后？怎么理解，为什么？