It's not really possible to tell you the page number of this quote without knowing what edition of the book you have. I can tell you where the quote is in relation to what happens in the book, but I can't give you a page number.
It comes from very late in the book. Montag has already escaped and met Granger and the others. Montag is still looking back at the city and thinking about his wife. Just a little bit (maybe a page or two) after the quote you cite, the city gets bombed. So we are talking about very late in the book.