Please help with subwoofer

Hi. It's my first time here so sorry if I'm not posting this in the right spot. I have a 12" Type R sub in my car, and yesterday this little black rubber piece that kind of holds the sub flapped up, making it sound like crap. Here is what I am talking about :
http://www.geocities.com/tuckitty820/TypeR.jpg
See where the arrow is? That's what's flapping up about 1/4 of the way around the sub. Can I glue this back down? And if so, what kind of glue and where do I get it?? Thanks for your help!!