How Do I fix or reinstall the Fixer Theme or fix the header?

I was having recurring trouble with malware infecting this site and installed Wordfence security. The header.php file was detected as having a string that matched known malware so I allowed Wordfence to delete the file. Now when viewing the site I get some text at the top where the header used to be so apparently the header has been deleted completely. I'm not sure what I need to do to restore the header and I could really use some help getting back to the way it was. The site is about 90% completed so I also don't want to lose the content.