Bless you for taking in these homeless, lost and forgotten animals.
You're doing a good thing, although $80 for a weeks food seems a bit
much! Those kitties must be eating really good!
Call all of the local Vets and ask them about cat rescue organizations,
also try contacting the American Humane Society and SPCA. Any or all
may be able to put you in touch with local organization that will
assist you with the care and feeding of these animals.
Another source is Pet Finders and the Internet Lost and Found.
I care for a small colony of feral cats myself, there are only five
main individuals and several more transient toms (haven't been able to
trap and neuter them yet), I spend maybe $25 every two weeks to feed
these precious forgotten spirits, and they do eat well. I found help
with them through Indy Feral, so you might try contacting the Humane
Society in the closest large city to you. Also, since you fell most of
these kitties are refugees from Hurricane Ivan, try speaking with your
local newspapers alone with TV and Radio stations. Some of them might
be interested in running a "Human Interest" story about them and
finding their owners.
I hope all this will get you the assistance you need in caring for and,
hopefully, finding their owners. Good luck to you and many Blessings!