Find and replace words from excel list

Hello all
i’m new on this and i appreciate if you help me on this. (Quark8 and MAC at all), but on my first job week i had a challenge to win.

Challenge is:

From excel or txt file comma separated, i’ve 2 collums (collum A= Existing Words) and (collum B=Words to replace) .

So, the steps are:

source documents are PDF files or QuarkXpress (8.0.16), place in a folder
execute the script that will
Rename existing files and copy to a subfolder
Find and replace words from excel
Highlight words that was changed
In the end, user wants to see, how many words were replaced.

The best choice is applescript? Or from Xtension? or something else?

In case of best choice be applescript, can you please help me on this?