For a while the car has made a knocking sound when going over a bump or dip in the road ... but only when going over a bump.
At first I thought it was the suspension, but I found that when the knocking is at its loudest, the steering is slightly odd ... meaning, I can wiggle the wheel slightly and the wheels dont feel as if they are turning, it also pulls to one side when breaking and then centre's iteself when not braking.

The car went to the garage yesterday, and my mate said he thinks its the steering rack is getting worn.

Where could I get a replacement ? and how much (average) would it cost ?
I assume a XR3i would fit ?