Find a cousin or relative in Army. Auction in Pindi is done at CMT Golra, periodically.
You can also visit Islam Sons at City Sadar Road and 26 number Chungi near Motorway Chowk. You'll find auctioned vehicles at both these places. They usually buy whole lots. But do check the auction voucher, it shouldn't be more than 2 years old, otherwise ETO Islamabad shall not entertain for registration.
Please do consider following points before going for this project:
Original engine is 3F, which consumes too much petrol.
Engine swap is costly these days.
Leaf spring suspension is stiff so ride will be uncomfortable.
There is no A/C.