Auto-Replacing Text Variables with Date, etc.?

[studioincavo]

Hi there- I produce a weekly podcast from a script running in a program called Celtx. Some portions of the show retain identical structure each week- the only differences are "variables" like [DAY] and [MONTH] that I insert into our template- how can I make Automator see [DAY] (and even [MONTH] too) and replace it with the date of the nearest Friday? I have other variables too, that refer to segments written by contributors- I imagine that there's a way to get Automator to paste in these text segments over top of variables like [BIG STORY]? Thanks so much.