I'm glad a custom window was done up, as I've got little experience with them. On a side note, you could also use this, which puts the date & time (adjustable to your preferences) in the title bar
Code:
on *:start:{
.timertime -m 0 500 titlebar $!asctime(ddd mmm ddoo yyyy @ h:nn:ss tt)
}

Note: This will replace your current titlebar display, not append to it.