If you mentioned which flavour of Linux you had, it would be easier to help. Most systems have some method of upgrading which is particular to them, the well known ones being Debian with .deb packages (installed using apt-get/dpkg) and RedHat/SuSE/others using RPM (.rpm files). The easiest way to upgrade is to get the latest package for your distro.

The other way is to install a compiler (gcc usually), grab the source, and compile it yourself. (Though that usually involves the installer asking you several questions you need to know the answer to, like where to install it, whether it should include the library paths of the old perl modules, etc.)

C.