To partition and rsync without installing the OS, use a boot CD style distro; Knoppix is the archetypal example. Boot the machine with Knoppix, fire up fdisk in an xterm window, e.g.
fdisk /dev/sda, if /dev/sda is the disk you want to partition.
then make the filesystem with mkfs.ext2 on, say, the first partition
mkfs.ext2 -i 128 -c /dev/sda1
then mount the old filesystem somewhere
make mount points
mount /dev/sdb2 /mnt/oldroot, assuming your old / is on /dev/sdb2
mount your new root
mount /dev/sda2 /mnt/newroot, assuming your old / is on /dev/sda2
then rsync -avR -x /mnt/oldroot /mnt/newroot
You can also do this from your existing setup by booting into the old setup; obviously then you don't have to mount / on /mnt/oldroot
Repeat for the /boot partition (if it is a separate partition), then the GRUB files will be installed, though grub itself will not. Tou can install grub to the new disk with either the grub prompt (type "grub" and find to find the files and install.) grub-install /dev/sda usually works too.
check man fdisk, man rsync man mkfs.ext2 to catch any typos I may have made