Re: Obtainign a Pakistani Visa
I applied for NICOP online on NADRA's website from the U.S. I got it delivered to my home with First Class U.S Mail in about a month (33 days to be exact). Not that bad. You can do everything online, including photograph submission. My credit card was charged $24 by NADRA.
Oh about the question, if your old expired passport has a valid visa, simply attach it to your new passport while traveling. I have done that many many times.