Code:
  inc %num [ $+ [ $2 ] ]
  if (%num [ $+ [ $2 ] ] > 1) msg %room $2 has been here %num [ $+ [ $2 ] ] times this week

You don't need evaluation brackets with /set, /inc and /dec. It's ok if you changed Fantas' /inc because of personal preference, I just want to clear up that his way was equally correct (and slightly faster). And a little detail (call me picky), it'd be slightly faster if you used
Code:
if (%num [ $+ [ $2 ] ] > 1) msg %room $2 has been here [color:blue]$ifmatch[/color] times this week


/.timerQ 1 0 echo /.timerQ 1 0 $timer(Q).com