Claire, if it is the phone with the extra-large buttons you are looking for, I'd say check out eBay. Might be a bit of a needle-in-the-haystack search, though.
However, in your area I would think there might be some blind-assistance organization(s) that could help. Then, of course, there's always searching the Internet for such an organization.
"As a girl I had zero interest in the stove." - Julia Child
This is real inspiration. Look what Julia became!