Files in the quarantine are backups of infected files that were found and fixed on your server. They are saved in /wp-content/uploads/ and are completely harmless there but you and delete them with an FTP client if you want to.
That said, it looks like you still have some viagra links on your site. There must be some injections into your code that my plugin missed. If you are willing to give me WP Admin access to your site I can look for the rest of them for you.
You can send credentials directly to me: eli at gotmls dot net