First:
Backup your database (and if it was me, I'd offload a copy from this questionable host...)
Second:
Backup your Moodle data directory (same recommendation as above)
Third:
Backup your Moodle directory (same again...)
Now:
When your enter http://www.yoursite.dom/index.php what do you see?
If you see your site, you might be ok, check around.
If not, follow the upgrade instructions, here http://docs.moodle.org/en/Upgrading.
If your database is intact, as you indicate, you should be able to hook back in without loss of data (presuming none was lost when your host did their thing.)
Good luck.