The might be a few alternatives as what I was proposing would take a fair time and rely upon you having the same amount of free space that the root volume has and would not be easy to, it would be easy to screw it up and loss the lot.
The Question is why have you run out of Inodes, I assume it was a standard installtion and that you did not customize the filesystem (which you can do when you create the filesystem by hand)
Normally Inodes will fill up because you have lots of little files (each file requires an Inode), therefore running out of inodes first but leaving you with plenty of free space.
You could locate the these small files and create a new filesystem with additional inodes using the mkfs command and the move the files to the new filesystem. Or alternativly backup your important data and re-install.
Normally best practice suggest that you have a sperate / /var /home, and then also create other filesystems for your data / users etc.