wheel problem

[jivadent]

My 300SD has a problem with the left front wheel. It makes a noise when I go over bumps, and when I turn hard right it slips and makes that screeching noise. I took it to a Tuffy for a diagnosis and they told me the groove in which the ball joint of the wheel fits is too loose, and it needs to be replaced. The problem is that the whole housing needs to be replaced when you do that, and the parts are like $700, labor $500 so it's real pricy.

I have 3 questions for you guys:
1) Is this something I can fix with a mechanically inclined friend, or do I have to take it into the shop?
2) If I can do it myself, what part of the MB CD would have instructions on that? I've looked all over it, but I can't find it.
3) Has anyone had this problem with their car? If so, how much did it end up costing?