Kathleen,
Where is the green bit? If it is in the center of the plant, you could try removing all the dead tissue, putting the plant in a bright spot with normal watering (little less than normal until it recovers.)
If the green bit is on a leaf somewhere, and it looks like the center of the plant is dead, you could try snipping that part off the plant and rooting it like you would to propogate a strepto.

Don't consider myself an expert- just comes under the "what I would do" heading. Hope it is helpful...

Let us know how it goes.
Andy

Oh dear, hate to say it, but she's officially toast. The bit of green withered ever so quickly into the rest of the necrotic mess, and even though I cut off all of the dead matter, there is no more green.

=( Rats, rats, rats. And I really liked that bloom.

Kathleen

p.s. Thanks for your suggestions anyway, Andy. =)