It mostly depends on the complexity of the script. One measurement of this is the download size. If it is just a few kilobytes, most likely making a new version of the code would be simple. If we are dealing with a few megabytes, it is probably a much larger task. If you want to PM me some info, I will be happy to take a look, as I quote stuff like this all the time.
(note: I am going to a funeral, so I may not answer today)

That's like asking how much it costs to have a taxi take you where you're going. Without more detail, the answer is always, "It depends!"

Can you be more specific about what you have in mind?