加国移民，寄护照后大概多长时间可受道移民纸？

I received the 3rd letter last Monday. I was asked to submit my passport and 3 new pictures. I got every thing done and mailed out them the next day by express mail. Do you guys know how long does it usually take to receive my landing documents? I am in a hurry as my working authorization is going to expire by the beginning of this September. By the way, I am in Vancouver. Thanks.