Steve makes many good points.
Do you know anyone with construction experience
who could look at it with you? A porch should have
a slight slope to allow water to drain off. Typically
an 1/8" drop per foot. Also a porch is poured seperate
from the slab, so there will be a crack, but is
it so wide it signifies a problem? The windows
pulling away may or may not signify a problem. Need
more specifics on it. Is it caulk from the Window
to the siding that's seperated. If so, what type of
siding? Foundation repairs to a slab home can be
extremely expensive, be sure of what you're getting.