You can actually leave it as it is, it'll most likely be fine, if the script is on the same server as the database (which it will be most of the time with shared hosting) then "localhost" is usually fine.
when setting up your database add it through your control panel. Then take the exact name and use it in the config php along with your username and password. If you get a db error then you did not put the right database info in. If you need to add the .sql just go under the database name and click sql then browse to it on your computer and hit go