1. By .xyz, do you mean a text file with x, y, and z coordinates?
If so, use Raster To Point (conversion toolbox) to make a point file
then use Export Feature Attribute to ASCII (Spatial Statistics)
to get coordinates and attribute values to a space, comma, or semi-colon delimited ASCII text file.
if you want isolines,
try Contour, which needs a Spatial Analyst license.