You can probably upgrade the kernel the same way that would normally be done.
1. get the lastest stable kernel source.
2. unpack the source to /usr/src
3. cd /usr/src and create a symlink to the source
Code:
ln -sf linux-<replace with latest kernel version here> linux
4. run make menuconfig weed out the devices you don't have, and add devices you do have.
5. make sure your /boot partition is mounted if its on a separate partition, and run make && make modules_install install
6. edit your grub.conf or lilo.conf
(remember to keep a backup of your kernel)
7. reboot and select new kernel.