Changing the rear wiper blade Renault Megane Hatchback Dynamique?

I need to change the rear wiper blade on my Megane Dynamique and the wiper has a cover over it, and try as I might it wont come off = I can't find the book that came with the car either. I could probably force it off but I'm sure its going to break and I cant afford to buy another new part. And yea, i know i sound like a girl, well thats because I am!!! lol