What Is The Recovery Time After Knee Replacement Surgery?

My Mother needs knee replacement on both her legs. She is 64 years old. I have consulted a couple of Doctors and found out that the hospital package for this will cost around 4 lacs. Is this right? Is there a best hospital or a surgeon to go to? I am considering Medanta hospital in Gurgaon for this.
Is the procedure carried out in all leading hospitals the same?
Are the artificial parts used for this surgery better in quality and performance at one hospital than the other?

My other questions are:

1. How long does it take to recover fully?
2. Can a patient sit on the floor, or sit cross legged after recovery?
3. How much can a patient bend his/her legs after full recovery?
4. Is it possible to climb stairs and walk without a stick after full recovery?
5. Does the artificial knees wear out faster if a patients walks more after surgery?
5. How long does the replaced knees last?