take a look at this:
As for moving home. put you new disk on the machine. it will be hdb.
Then copy everything in /home to a temp directory. Edit your /etc/fstab file to make /home mount on /dev/hdb1 or whatever. mount the disk (mount -a) Then move the stuff in the temp directory back into /home. This is quick for you as you only have a very small amount of data in /home.
Although i don't really see what the benefit of a large root partition is.
Any more help with mounting etc please repost.