A .ram file is just a text file with a link to a .rm file. Hopefully that link will use HTTP, so you can just copy the link and paste it into Safari's Downloads window, to download the actual video file. If you're unlucky, it'll use an RTSP link. In that case, you'll need an RTSP downloader, such as Hi-Download (for Windows).
In either case, you'll still need the .rm conversion software.