Step 1: Back Support
Take two pieces of scap wood, just long enough to expan the hole. Then secure with screws.
Step 2: Screwin It Together
Screw the stucco piece to the wood.
Step 3: Quick Spackle Fill
This is quick drying spackle, since it's a rough stucco you don't have to be neat.
Step 4: Paint!!!
You only have to wait fifteen minutes or so for this spackle to dry. Then you can paint.