Replacing Power Steering Lines

My mother took her 99 Ford Contour to the dealership because of a noise when turning the wheel. They told her she needs the power steering lines replaced because they are rusted out and leaking. They say she can add fluid when needed for now. The price they quoted for four lines and cooler replaced is $681.00. This seems a little high to me. They say the parts are no longer made but they were able to get the parts in only two days. Is this something I can do myself? Or should she get her lines replaced somewhere else? When I added power steering fluid and the noise has stoppped for now. Her car is 99 Countour SLE 4 cyl. with 48,000 miles on it. Thanks,
ecnar

price does seem steep but this job is a pain in the butt it may be worth it if you don't have a lift