Is there a faster method.. would scp or rsync increase the download
speed on the new server.
scp would not be any faster - there would be a slight overhead of the secure connection, but its negligible.
rsync would only be faster if you already had some files on the destination server - that way you aren't copying everything wholesale. However in your case I believe you are provisioning a new server so rsync would not provide any significant gains.
It sounds like there is some throttling or bandwidth restriction on your old server; because your limits seem artificial; explicitly restricted rather that a physical connection limitation. I would suggest talking with your NOC support to see if they can do anything about the restrictions or as mdpc said, use the old fashioned method. Ask your NOC to create a backup (simply cloning the disk would be fastest, burning DVDs quite slower) and then have it couriered over to your new data center.