Well, you'd have to sign up on the forums to be able to access the page etc. Here, perhaps just do this...
Replace: var today=new Date()
With: var today=new Date(GMTmilliseconds)
Replace GMTmilliseconds with, obviously, the current date in GMTmilliseconds. (i.e. 873991800000). Try it out, see if the script works. It doesn't for me, see if u can get it to work.