Toyota Repair: Rack and Pinion, power steering rack, toyota corrolla

Question
my wife has 1998 Toyota Corrolla LE. we get regular maintence from Sears Auto. Questions i have is for past few days its making unusual noise which is coming out from the passenger front side, i took it to the Sears they were unable to diagnosed the problem, However, took the vehicle to local repair center, i was told that the power steering oil is leaking it could be the hose or Rack and Pinion. repair estimate i was given is about $350.00 to $750.00 depending on what nees to be replaced.
i like to know if this is a reasonable cost to repair.
Thank you  

Answer
First of all I would recommend going to another place that can diagnose the problem with more accuracy, "it could be this or that" is not an accurate diagnosis, consult someone that can tell you exactly what the car needs, it's not that hard to determine whether the power steering rack, the power steering pump or a hose is leaking, maybe going to a toyota dealer would be better and in this case may save you some money.