Alright, when my forum gets back up tomorrow, my host is going to upload all back up files tomorrow morning. When those files are back up and the database from the day before is up, can I over write that database with the newer one I have.
If so how would I?
yes, you can. however ensure that you have clean database to restore (not the hacked one)
and it might be better to keep a backup of recent database provided by web host
How will I add it, do I just collapse in SQL and upload?
if your host has provision for using multiple databases then you can add your database backup
as a new database and connect through changing database details in ~/inc/config.php file.
or you have to remove existing database (eg. drop all tables) and import your database backup & connect to it