I am confused because in the letter it stated that "If you have a Confirmation of Permanent Residence (CoPR) document in-hand please send it along with one photo". while they could have just said send a photo along with this letter.That is CoPR, as advised in letter, you should send copy of it with a photo to given address to get your PR card. I would recommend doing it right away. Though you can use the letter as proof of PR for upto one year from the issue date.