Adding space to existing mount

I am on Red Hat Linux 4.7.

I am getting this error message:

Preparing... ########################################### [100%]
You have insufficient diskspace in the destination directory (/usr/lib) to
install xxxxxxxxxxxxx. The installation requires at
least 1.5 GB free on this disk.
[root@jhlinux downloads]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda8 4032092 2316496 1510772 61% /usr

What can I do to add more disk space (2G) while preserving the filesystem ?

I was thinking to create a new mount for /usr/lib but I am not sure if this is the right thing to do. Please advise and thanks in advance.

I decided to reinstall the OS.

Just an FYI, you do not have to reinstall the OS. You can usually do this with a bootable linux CD.

Also, df -m or df -h make for easier readable formatting for humans. df -k usually works better for making output that can be worked on by machines and other programs/scripts.