@aijazkhalid, the 1992 Swift was sold in a 2 door configuration as the Cultus GTi in foreign markets. IF this car came with rear disc brakes, you might be able to use them for the swap, though I highly doubt any stuff for those cars is available in our junkyards.
A few words of caution before you go on a wild goose chase now:
Converting to rear discs doesn't automatically solve all your braking issues. The front brakes do >80% of the braking. The job of the rear brakes is to provide additional drag while keeping the car's rear end straight and planted firmly on the ground. Just one look at the size the tiny drum brakes on the Swift should give you a hint of how little work is expected of them. Almost any disc brake conversion you do that is not OEM for this car will be larger in size than even the front brakes causing very poorly balanced brakes and a car that takes even longer to stop.
Rear disc brakes also require swapping to a larger diameter master cylinder and possibly bigger booster as well because of the greater volume of fluid required to operate 4 wheel disc brakes. I installed rear disc brakes on my Jeep CJ7 recently, and I still had to change the master cylinder as the pedal would sink all the way to the floor with original cylinder. Keep in mind, I didn't even use an oversize performance set up, just Suzuki Potohar discs with Corolla rear calipers (same as 86 Pajero rear calipers, but easier to install). Braking is pretty much the same as before, the main improvement being in pedal feel, brake modulation, and vehicle pitch. Now I need to modify my parking brake cables for it to work with the disc brakes. That's something you'll also have to worry about too.
All in all that money would have been better spent on other things. It was not inexpensive and the improvement really is marginal. If you want to improve braking performance, look at upgrading your front brakes (larger discs and calipers) first. Also remember that larger alloy wheels and oversized tyres ruin braking performance. Lastly, remember that a 1992 Swift will never have the same braking performance as a 2011 Camry, short of installing Brembo binders that cost more than the car itself is worth.