Don't be baffled.

First, rename the old home (old_home) will do. Next create a new home directory alongside it.

Next mount the new home temporarily (something like -- adjust to suit your system) mount -t ext3 /dev/hdc? /home

Copy everything you want from /old_home to /home

edit your /etc/fstab. You want a line something like:

/dev/hdc3 /home ext3 auto 0 0

the auto here is crucial -- omit it and you'll have to remount it by hand every time you boot.

Reboot.

Chances are that you'll only be able to log in as root. Don't panic. As root (hell, use Kde to do it) chown home.

Once you're sure everything is OK, grab back a little space by deleting /old_home.