No one likes to hear it but the answer is truly that she needs a vet visit right away to treat her MBD and whatever else may be ailing her.
Without it she will not survive much longer.
With treatment right away, she probably will survive.
MBD is when the bones have been giving up their calcium for some time in order to keep the heart muscle, tongue, intestines and other muscles working.
There are several reasons this can happen and it is important to both correct the cause and get treatment to immediately increase blood calcium levels.
We will be happy to help you figure out why this has happened but a vet visit is truly needed because she is in such bad condition, she is in real danger of dying very soon.
You can get to a pharmacy and buy calcium glubionate syrup such as this http://www.amazon.com/gp/product/B00112G29O/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 or another brand and begin administering 1 drop in the morning and 1 drop in the evening but she really needs to get a calcium injection from a vet.
I wouldn't just order it online because her condition is too serious to wait.
The vet should be able to provide you with calcium syrup.