Assuming you already installed the other kernel, just add an extra section - copy that one, paste, and edit - with the other kernel and a different name:
I'd suggest avoiding the "recent" kernel for now - the aim is to see if the smp kernel (check for the right name in /boot) gives you the other "core". Upgrading to a newer kernel is another kettle of fish (in particular, because the stock 13.37 lilo may not recognize it).
EDIT
"Select to install" just by editing the config file, save, exit, and then click on the button, whatever exactly it says, perhaps "Install Lilo".
Ok now I have a real problem, I changed to vmlinuz-huge-2.6.37.6-smp, installed and rebooted
Now I cant see my windows partition and worse... I cant even move the mouse or use the keyboard...
I reinstalled with the cd and still the same... i dunno if i had some kind of error when installing it again but what should i do now?
Im desperate using my bros laptop to tell you this...
That's not the right name - as I said, "check for the right name in /boot".
However, you should still be able to boot into the installation using the other kernel. Then repeat the process with lilosetup, and make sure the kernel name for the smp kernel entry corresponds to the file you see in /boot.
If not, you may need to use a Live CD as a rescue disk. Within Live, you can run lilosetup. Please read back over this thread and the one I linked to above.
With these kind of operations - especially when problems crop up - it's worth taking things slowly and double checking.
In /lib/modules/ the module should be the same as the kernel like 2.6.37.6 or 2.6.37.6-smp. Could be even both modules for either event.
If the modules are not the same as the kernel there will be no KB and mouse.