Hey, I just got After Effects and need help with something.

I've imported my desktop image and want to make it into a Dreamscene Background. I've set up the effect I want to use and set the keyframes and all that, but I want to change the Affected area so that the effect only changes what's going on inside the blob and preserves the biohazard symbols. (See images below.) Is there any way to do this or am I out of luck?

Click to enlarge.