Restore the modified file with a working copy from the theme archive.
You might have made an error in the code changing that string with one including the apostrophe (which is also a special string delimiter in PHP).
The safer way would be to customize that text using theme translations (we have two tutorials about creating theme translations).
If you like our creations, help us share by rating them on WordPress.org. Please check the available documentation and search the forums before starting a new topic.