Adding a turbo to a diesel increases more torque than horse-power. However, the conversion to turbo is not that difficult and pretty cheap. I believe you can get all parts, turbo, manifold, piping, intercooler, fuel pump for around Rs.15000/-
Is this the new corolla or the old one? Intake and exhaust modifications work great on the old one because the exhaust is very restrictive, and such a conversion frees up a lot of power that the engine simply wastes in trying to breathe!