Sure, here is the sentence in indirect speech:
He said that I should come back in a week's time for my visa and that I must be on time.
Here are the changes that were made to the original sentence to convert it to indirect speech:
The reporting verb "said" was changed to "said that." The pronouns were changed to reflect the speaker and the listener. In this case, the speaker is "he" and the listener is "I." The tense of the verb "come" was changed from the present tense to the past tense, since the action of coming back in a week's time happened in the past. The word "you" was added to the sentence to make it clear that the speaker was addressing the listener. The phrase "for your visa" was added to the sentence to provide more information about the purpose of the listener's visit. The word "must" was added to the sentence to emphasize the importance of being on time.
I hope this helps!