You need to make changes in one of the PHP codes of wordpress for this. The sender email address is defaulted to firstname.lastname@example.org in pluggable.php file.
Open the pluggable.php file present in wp-includes folder and make changes in 3 places...
if ( !isset( $from_name ) )
$from_name = 'Wordpress'; <- change it to your desired name
Below the above codes, you will find this line...
$from_email = 'wordpress@' . $sitename; <- replace wordpress with admin/support or your desired email
and around line number 1470, you will find this line...
$wp_email = 'wordpress@' . preg_replace('#^www\.#', '', strtolower($_SERVER['SERVER_NAME']));
<- replace wordpress with admin/support or your desired email. Make it same as $from_email
These changes should fix the issue.