Magik,
I'd go with the wheel bearing replacement first if that's about to go...although if the ball joint goes, you won't be able to drive either.
You really should take care of both of those first and then the exhaust when you can. I have seen those ball joints go a while, but if it's already detached, it should be replaced ASAP. You should be able to do the ball joint yourself and save some cash...
Unfortunately, it's pressed in to the upper control arm and the whole arm needs to be replaced...hence the cost.
Bogatyr