C280 rear differential and arm bushings

[crit1]

I was told by my local shop that my '95 C280 has cracked front lower control arm bushings and the rear differential needs a complete reseal (leaking oil). Can someone explain to me what this means, if the car is safe to drive (they didn't say) and how expensive these items are to fix? I just got the car and have already replaced the wire harness and the head gasket. My wife is starting to get on my case about spending too much on it. Ouch!!