Anyone know how to replace? Also, where is the best place to purchase it?

 

Those plasticky stuff which is on the blade, from the base needs to be snapped off. You will feel they are breaking off, it has got a stiff hold not to worry .Just give it a slight pressure to pull it off, and there you go.

 

the plastic piece that covers the nut that holds the arm in place is easily removed. removing that piece allows you to pull the arm out perpendicular to the rear window which in turn will make it a hell of alot easier to replace the wiperblade.