Adding side skirts to my 89... what do I need?

[aaron7]

I picked this stuff up at a parts yard for $70 (couldn't find the side skirts anywhere else for this cheap!) plus I got the rear visor.

Anyways, I pulled the side skirts off a 1988 MR2. I saw there were white angled plastic mounts that the skirts screwed into, but I couldn't get them off (plus the yard was closing in 10 minutes!)

First, how do the mounts attach to the car? Will I have to cut big holes in my MR2 to install the skirts? Second, can I buy those mounts at a dealer or something? I really don't want to go back to the yard and fight with them! (the parts that is :P)