2nd question unrelated to the first...

How could I get the following command to be channel owner only? and add a stop function?

Code:
on *:TEXT:!raffle:#:{
  if ($nick isop #) {
    set %raffle $rand(1,100)
    msg $chan /me First person to guess the number between 1 and 100 wins!
  }
}


on *:text:*:#: {
  if ($1- == %raffle) {
    msg $chan WE HAVE A WINNER  
    msg $chan /me The Winner is $nick with the number %raffle $+ !!!!!!
    unset %raffle
    .timerraffle 1 10 msg $chan CONGRATULATIONS $nick !
  }
  else { }
}