Crack in slab and leak along fireplace (photos) - how bad?

[Ludmila M.]

In your opinion, how bad and expensive are these two problems:

1. Crack in a slab foundation.

2. Water leak behind the wall that surrounds fireplace. Water stains are visible along this wall from the ceiling (two-story room) all the way down to the floor, with corresponding floor damage.

The house was built in 1994. 

[Sorry some of the photos are sideways, I can't figure out how to rotate them.]

Thank you!