There are three plugins that, at a bare minimum, you should install. They are WordFence, WSD Security and the TimThumb Scanner. All are free plugins that you can download from your Plugin area of your WP Admin area. Get these setup to add more protection to your dating site.
In a nutshell, you want to change your default admin username to something else, don’t use the default wp table prefix (wp_) when you install WordPress and another is to protect your /wp-admin/ area with a .htaccess file that blocks all other IP addresses with the exception of yours. You can read more about how to setup your .htaccess file in the Support Forums under Security.
The last thing is have good backups. There are many backup plugins out there that can do that for you. Be sure to read the support forum thread about backups. We’ve posted a really cool solution there to automate your backups that get uploaded to dropbox.com and all for free.