Forums Scripts & Popups Request: Specific Timer :)

What I have so far is this:

menu channel {
Announce
.Start: .timerAnnounce. $+ $chan 0 259200 msg $chan $$?="Enter Message"
.Stop: .timerAnnounce. $+ $chan off
}

But I still can't seem to get it to check if my last message was posted in the last 72 hours if so then hold until 72 hours has passed.