Originally Posted by lpsavoie
...right now, I have /dev/sda1 (/), sda2 (swap) and sda3 (home) as primary partitions.
Well, that's only three. Unless there is another one that you didn't mention, you have room in your partition table for one more. It can be an extended partition and hold many more logical partitions. So just use your favorite partition manager to create an extended partition. Then create the logical partitions that you need inside the extended partition. The real issue is whether you have any more space on the drive for another partition. That's a different matter. If you have that
problem, use the partition manager to shrink an existing partition(s) to create some free space in which to create the fourth partition.