Barbara, before you buy a new one you might want to try to unmount Dasher and remove the foam.
I know on some of my older SU stamps when I unmounted they separated from the foam easily. Might not be as easy with a newer stamp but it's worth a try. Check out some of the unmounting threads that are out here.
If you are successful; there should be enough sticky stuff left on the back of the rubber that Dasher will cling to a clear block. At that point you will probably want a foam pad or magazine under your paper as well.