My guess is that somewhere in a theme or plugin is a function that's modifying the excerpt "Read More" text. See: http://codex.wordpress.org/Plugin_API/Filter_Reference/excerpt_more
First, disable each plugin individually and see if it goes away - that will identify if it's caused by a plugin. If nothing happens after they've both been disabled it's probably in your theme. To confirm you can switch to the default theme, 2010.
If it's in the theme, look in the functions.php file for something that says add_filter('excerpt_more', ...
If you either remove or comment this line out it should fix it. Make sure you are making these changes using an FTP editor or something other than the editor in the backend of WordPress. If you do something wrong and create an error, you won't be able to log back into WordPress to fix it.