My 96 avalon had been leaking power steering fluid for almost a year. A few months ago it was so bad you had to add fluid every time you drove it. About 3 weeks ago, it quit. No fluid had to added at all. Then yesterday, it wouldnt steer, so we added fluid. It gushed out under the drivers side live a river. A friend looked under it and said the boot is torn large enough for him to put his fingers in it. What boot? How do we replace it? Is it expensive?