Your question has a minor issue and it is that the p2c-layer.php file does not exactly hold the content you are describing. Anyway, just use this content:
QA_USER_LEVEL_BASIC => 'Registered+',
QA_USER_LEVEL_APPROVED => 'Approved+',
QA_USER_LEVEL_EXPERT => 'Expert+',
QA_USER_LEVEL_EDITOR => 'Editor+',
QA_USER_LEVEL_MODERATOR => 'Moderator+',
QA_USER_LEVEL_ADMIN => 'Admin+',
QA_USER_LEVEL_SUPER => 'Super Admin',
I took a very quick look at the plugin and it seems it should work as expected. Please, give it a try and report back.