GPS is free to use, but maps generally aren't. The problem of having GPS to work in Pakistan is that there aren't no maps available.
I have heard/saw/read that Garmin now has maps for Pakistan too, but I highly doubt it will be any more than a few major cities.
Your line of research can be to find out what maps are there on your N95 (Probably Nokia's own maps) and see if they have one for Pakistan.
If not, either wait for one or try to chalk one out yourself 