U can add brake boosters to your car to improve braking performance. Dunno if it is true or not but have heard that brake boosters can be fitted only to MPFI cars
You can also check this out -
Car Parts Wholesale,Engine Carburetor Parts,Car Engine Parts Supplier,Carburetor Parts Supplier,Car Engine Parts Wholesale
They state they have parts for cars like the 800, alto, swift etc. And they make brake pads and shoes along with various other parts for these cars. Since it seems locally made i dont think it will be too expensive either.

....Hope it helps