You can most probably buy a ready made radiator from magazine lane Karachi, it would be twin pass radiator - make sure you tell them its for a 1980 corolla and not a 1982 corolla because the top radiator pipe is at the different position in the 1982. Its a 30 minute job to replace the radiator in your car as the shroud is 2 piece, once undone the radiator is unbolted (4 bolts) from the frame and slid up and out. make sure to get the correct design fins for maximum cooling efficiency.
This applies only if you have the general imported model corolla which was simply called toyota corolla or corolla DX, If you have the later JDM import called SE or GL model (huge bumpers) then your radiator MAYBE offset to the side of the car and have electric fan.
I doubt your engine will have the clutched fan as most general imports had the silly looking 4 blade fan in a gigantic air shroud. Later on mechanics replaced it with either a 6 or 7 blade fan which caused enough air noise to challenge a dump truck.
you can opt to install a clutched fan, it requires replacement of the shroud for the larger fan and also mounting of the clutch on the waterpump pulley. Make sure you service it first, its silicone oil is sold as a spare part in little bottles.
Always use a genuine thermostat valve and radiator cap and make sure the expansion bottle is connected with no leaks in the pipe. The needle being in the middle is normal position, if your system was boiling out then you have some leaks.