Ouch!

Sounds like you have a bunch of problems.

First, it sounds like the slab wasn't properly waterproofed when it was laid. Up here in the Northeast, it's common practice to lay heavy plastic sheeting before pouring a slab, to avoid this kind of problem.

Second, you have a serious groundwater problem. If the water is coming up through the foundation, that means there is hydrostatic pressure enough to lift the water against gravity. Maybe only a few PSI, but multiply that by the square inches of your slab and you will see why it is cracking. I would guess the flow from the Condo roofs is actually creating a spring under your foundation. During full moon/high tide times, the water table in the whole area is higher, so the water has nowhere to go.

My first point of attack would be the water coming up under the slab. Here in the Northeast a slab on footer is usually a basement, so the usual solution is to cut a sump pit in the slab and pump out the water as it enters the sump, lowering the water table under the slab. BTW don't make the common mistake of pumping the water outside only to have it seep back under again- you waste a lot of energy pumping water in circles that way. It has to have somewhere to go.

The second point of attack is the water getting under your foundation. Up here we would dig an interception drain all around the foundation and either lead it downgrade and away, to a storm sewer, or (worst option) to the sump pit. Whenever possible, let gravity move the water- it's free.

Based on your description, I think you are going to have a hard time keeping up with the water coming into the sump pit.

You could also consider (after doing the above) putting plastic sheeting on top of the slab, then building a floor above it with treated 1x4s supporting exterior or marine grade plywood. You will have to ventilate under the floor, keep humidity low and watch like a hawk for mold. Good luck.

Sorry, you have no choice...you have to drain under the slab. That means a trench around at least two sides, preferably more, with weeping tiles. Getting rid of the source will not really work since it is likely a water table issue.

Obviously this site is unsuitable to build upon.

Consider lifting house off of the slab and constructing a wood or steel framed first floor supported upon piers. Cut portion of slab lift and place vapor barrier under. Park car there.