you have a similar situation that you can adapt to your case (I copy-paste from there):
1) Use cfdisk to create a partition in a new disk or using free space in your current hard disk (call it emmmmm.... /dev/hd??)
2) mkfs.ext3 /dev/hd?? to create a ext3 file system in the new partition (you can use ext2, reiserfs... of course).
3) mkdir a new directory in your system... call it emmm... /home2_new
5) mount -t ext3 /dev/hd?? /home2_new
4) cd /home2 && tar cvf /home2_new/home2_new.tar * (with tar you keep the symbolic links)
5) cd /home2_new && tar xvf home2_new.tar && rm home2_new.tar
6) vi /etc/fstab and change the line with /home2 bla,bla,bla with /home2 /dev/hd??.