Prosites Plugin

Hello sir..
We have used prosites plugin. We need to change admin url to site at after free site register. i have chaged code in gateway.php line 701.
$content .= '' . esc_html__( 'Admin URL: ', 'psts' ) . '' . esc_html__( $blog_admin_url ) . '</p>';

TO

$content .= '' . esc_html__( 'Admin URL: ', 'psts' ) . '' . esc_html__( $site_url ) . '</p>';

i have showed clearly in attachment. Can you help me that which code i have to use there..?
Thank You.