I know this question has already been answered, but another option is simply to open the destination and source folders in Finder and then drag and drop them into the terminal. The paths will automatically be copied and properly formatted (thus negating the need to actually figure out proper file names/extensions).
I have to do over-network copies between Mac and Windows machines, sometimes fairly deep down in filetrees, and have found this the most effective way to do so.
So, as an example:
cp -r [drag and drop source folder from finder] [drag and drop destination folder from finder]