You can get Nasa coolant at cheaper rates compared to others look into bigger spare parts shops in RWP/ISL.
If you want something better then either buy ZIC(pre-diluted) coolant online from zicoil.pk OR buy Honda green coolant that would cost you 700 for a liter it would be concentrated you would need 2 liter of that concentrate and then mix it up with distilled water in 50:50 ratio.
Rest for power steering i think so you can get a EPS (electronic power steering) but that would require some skill to be installed and worked upon properly because EPS requires a speed signal from VSS for getting hard at specific speeds and VSS isn't present in carby cultus OR you can get a switch installed for disabling the power to EPS when using the car on highways or at higher speeds....
EPS would cost 6-8k Rupees for used setup.
You can also get the HPS of Cultus VXL but that would draw power from engine and would require timely maintainance it would cost 11-14k for complete used setup i guess.
For HPS Steering Rack would be changed.
For EPS Steering column would be changed.