This just needs a few extra lines, which I've inserted into your ON OP event. I added a little extra code just to make it easier to understand, and you can replace the %fulladdress.opped and %fulladdress.opper with the identifier calls that create them. This is also assuming you've already enabled /IAL ON so that it has the address of the person being opped. This is also echoing the messages to the channel instead of actually making them, so you can see what the message will be prior to putting it into production.

Code
on *:op:#: {
  if ($istok(#freeirc #Official #test1,$chan,32)) {
    if ($nick == X) || ($nick == *.undernet.org) { return }
    if ($nick == $me) { Notice }

  var %acct.opped , %acct.opper , %fulladdress.opped $ial($opnick) , %fulladdress.opper $fulladdress
  if (*.users.undernet.org iswm %fulladdress.opped) var %acct.opped ( $+ $gettok($gettok(%fulladdress.opped,2,64),1,46) $+ )
  if (*.users.undernet.org iswm %fulladdress.opper) var %acct.opper ( $+ $gettok($gettok(%fulladdress.opper,2,64),1,46) $+ )
  echo -g $chan /onotice $chan $opnick %acct.opped opped by $nick
  echo -g $chan /notice $opnick You're opped by $nick %acct.opper on $chan

  }
}