Indian Rupee -- I don't think so.. you can exchange them probably
USD - Best option
Restriction -- as far as I know you can bring in as many $$$ as you want and exchange them till the cows come home ... exchanging Rupees into $$$ I think there is some restriction.
don't bring Indian rupee(currency) unless you plan to travel to India by road from Lahore or fly to Delhi. You can bring atleast 10,000 $ cash with you to Pakistan. I guess thats the restriction on the amount of money you can carry at a given time. Besides that you can bring your visa or master card and use it here.