LinuxQuestions.org - /usr/src/linux-<kernelno> doesnt exist

Hi all.

Im just getting to grips with linux, but Ive had to move from my nice friendly college ethernet connection to my home wireless one.

I am trying to get my wireless driver to work using ndiswrapper, and I have realised that ndiswrapper wont 'make' because I dont have the kernel source files. I have read the previous posts on this topic, but they dont seem to solve my problem.

I dont have web access on the pc with linux on, so I have to transfer rpms over by usb rather than use yum, etc. The build I am running according to uname -r is 2.6.18-1.2239.fc5

The folder to which /lib/modules/2.6.18-1.2239.fc5/build and /lib/modules/2.6.18-1.2239.fc5/source expect to link to is /usr/src/kernels/2.6.18-1.2239.fc5-i686 but this does not exist. The only folder which exists in .../src is redhat/

From reading other posts, I gathered that I needed to download the relevant rpm. I downloaded kernel-2.6.18-1.2239.fc5.src.rpm and ran
'rpm -Uvh kernel-2.6.18-1.2239.fc5.src.rpm'

This just put the files in ...redhat/SOURCES. This problem is similar to the one described here: linuxquestions.org/questions/showthread.php?t=45982

however, unlike the problem described there, I cannot fix the issue by
'ln -s /usr/src/redhat/SOURCES/linux-2.6.18-1.2239.fc5 /usr/src/kernels'

or similar because linux-2.6.18-1.2239.fc5 does not exist.
linux-2.6.18.tar.bz2 does however, but extracting this to /src/kernel with the directory renamed appropriately does not fix the problem, so I have removed that little experiment.

Hopefully someone has experienced a similar problem, because I really am completely stumped.

Cheers
Seamus