Nope, just that theme.
I'm unfamiliar with the specifics of Host Gator, but in your CPanel you will need to find the "FTP" button, the one that lets you upload and delete files on your server. There, at the root of your site, you should find the base of the WordPress installation, a bunch of files and folders that looks something like this:
Find the folder /wp-content/themes/your-broken-theme/ and delete *just* that folder, it contains the broken theme. Upload the new theme in its place.
If you contact hostgator directly, they can probably help you do this, or show you how.