The mechanical parts of my steering were expensive, may be due to monopoly of the dealers, but the rear seat was quite reasonable.
Mechanical Parts Cost
Steering cross full column: PKR 10,000. (Got it replaced in half hour).
Air Bag/Horn strip: PKR 6,000. (Got it replaced in one hour).
Seats Cost
Rear Seat in exchange of my own AD Seat: PKR 11,500 (Including fitting). (Got it replaced in two and half hour)
If you want to change your front seats which I will not recommend you because AD van has its own front seats very comfortable and I also did not change the front seats. But if you go for them in exchange of you own AD seats then you will have to pay PKR 4500 including fitting. Front seats cost lower because the dealers can then sell the front seats in profit which they can not do with rear seat.
Location of the shops
Seats: Corolla Center, Chah Sultan Rawalpindi. Corolla Center is a famous shop there and you can ask any body when you are in Chah Sultan. It is difficult to explain the location in this message. But you can call me on my number 03345256838 so that I may explain you the exact location.
Mechanical and other body parts: Waleed Autos, Chah Sultan Rawalpindi. This is also a famous shop and you can ask any body there about its exact location.