Don't use the fiberglass repair. it'll be to brittle for the plastic and will eventually break away.
I'll look up on my thread my favorite way to patch holes and repair plastics.
I'll edit this posts in a few minutes with a paste from it.
Ok, this is from my Cliff Notes thread. It starts on page three and is done on page four.
A little farther in the thread is where I repaired my interior kick panels that had speaker holes in them. That might even be a more useful repair that you could use for your repair.
The Panel Bomding Adhesive is some incredibly strong stuff.