Retrofitting AC is a huge job and only doable if you buy a complete donor car, but finding one that will be 100% compatible for you is not easy, and finding someone to do it no easier.
You need complete AC system and a lot of other parts.
- compressor and brackets
- hoses (may be detoriated due to age and require replacing rubber sections by a hydraulics shop)
- front radiator assembly: condenser, radiator fan with thermo-switch and wiring (puntos with AC have 2 speed fan), dryer, radiator itself if your original is a small version (you need a 577 or 632mm core length version to improve engine cooling because condenser reduces airflow)
- right engine mount (aluminum arm is slightly shorter due to compressor bracket mounting under it)
- alternator is different, also different belts
- complete engine bay wiring harness with everything attached to it - really easier to transfer it completely than to try adding individual wires and figuring where to connect them. The whole harness enters the cabin in one point through a rubber seal and plugs into the rear side of fuse box. Beware, you need one for the same engine, if you have a 1.2 60 then only a 55 or 60 harness will do without modification, 75 is slightly different due to SPI vs MPI injection. Not many 55 or 60 cars have AC, 75 cars have it more often. 85 harness might be adaptable too, but don't try with 90 (1.6). I think it might be LHD/RHD specific.
- interior ventilation box with AC evaporator - requires dashboard removal. LHD/RHD specific.
- some interior wiring (AC switch)
- possibly some other stuff that I forgot.
I removed a complete AC system from a wrecked punto for later installation in my project cabrio (I haven't installed it yet) so i only have personal experience in what parts need to be removed from a donor car. It was a lot of work and installing it will be even more. I don't recommend it.
Power steering is less of a job, you need a steering rack (also LHD/RHD specific), crank pulley and belt, pump and bracket, reservoir and hoses. I think there is no wiring of any kind.
I don't recommend that either because a normal non-PS punto is not hard to steer if everything is good.
Check your upper strut mounts, old bearings tend to seize and make steering hard. Also check if they are oriented correctly, non-PS cars should have strut mounts turned so that the strut nut is facing to the rear (less caster angle, easier steering). With tyres no wider than 165 and at correct pressure, you won't need power steering.
How come your car has such a low mileage? That is very unusual. Do you have any photos of it?