Hi! Did you get a confirmation e-mail from DreamHost? This letter would tell you what machine your domain is on, and how to ftp before your domain name has propagated. I received a confirmation e-mail for each service (ftp, e-mail, etc.) as it was set up on DH.
Just download your files from the old server, then upload using your login name and pass, and connecting to the ftp server DH noted.
It can take a few days for a domain name to propagate- before it will show up in browsers all over. Start looking for this after a day or two. Once this is done, you'll be able to ftp to ftp.Hidawl.net.