I like to use the following command and key binding for situations like this:
command! RootRelaunchVifm :!sudo vifm %d %D
nnoremap <Space>R :RootRelaunchVifm<CR>
You hit the key binding to relaunch Vifm as root, enter your password, move the file to /usr/local/bin, and finally run :quit (or a corresponding key binding) to return to your regular Vifm instance.