Concrete and tile products can reflect and attenuate RF. Stucco usually has wire mesh embedded for structural support. The wire mesh makes a formidable barrier to RF.
If there's no metal or foil in the roof covering or structure, I would recommend an
Antennacraft HBU33 in the attic. You have enough signal per your report, I doubt the attenuation caused by the typical composition roof would cause trouble. Point it south to begin with, fine tune the aim from there. If the attic turns out to be a poor location, the Antennacraft products are fairly easy to re-fold, allowing you to move it outside without damage.
The heat wont cause trouble for an antenna, but may be a problem for a preamplifier... but you don't need a preamplifier. A common
passive 2-way splitter will be fine for sharing the signal between the TV and computer.
