in what way does this exchange initiate and anticipate the action of the play?

If my edition is the same as yours, then the famous exchange ends around line 470. But the exchange does both initiate and anticipate the action of the play. The action is Oedipus' simultaneous search for the truth (regarding the transgression that caused the plague) and his damning of himself in the process. In the exchange with Tiresias, it is clear to a knowing reader that Tiresias knows the truth but wishes not to share it. But Oedipus, so passionately devoted to discovering the cause, lashes out in anger and insults the seer for his refusal. Tiresias, himself now angry, tells Oedipus "This day will show your birth and will destroy you" (Grene, trans.) This is a summary of what will come, anticipating the action. But what really sets it off is when the King tells the seer that he is willing to be destroyed "if it has saved this city." By the end of their exchange, Oedipus is doubly committed to finding the truth even if it causes his own destruction, which is exactly what happens.