I am using a wordpress site. I just want to know , How to get a plain text from encrypted password(stored in wordpress database). I used the $wp_hasher->CheckPassword($
You will not be able to retrieve a plain text password from wordpress.
Wordpress use a 1 way encryption to store the passwords using a variation of md5. There is no way to reverse this.
See this article for more info http://wordpress.org/support/topic/how-is-the-user-password-encrypted-wp_hash_password