I know you've solved the problem, but people in a similar spot might want to check out gparted, a Linux boot disk/partition manager (free):
It does everything you need pretty easily and you can format your large external drives with FAT32, something Windows Disk manager won't do. A FAT32 external drive will work across many platforms where an NTFS partition won't. My TV has a media player app and USB port -- normally used for thumb drives to play downloaded video. But if you have a 500 GB external drive formatted with FAT32, suddenly a huge collection is plug and play.