this is trivial,
(read the net, use google, whatever,
but I have some time on my hands anyway
The "image=BlahBlah" is will load linux (you alread have this)
The "other" part lets you boot (ms) dos based operating systems,
this includes Win-XP.
Win Xp and 2000 are normaly quiet nice if they find a bootloader during setup,
lilo should not be overwritten.
So change your lilo.conf to something like this,
call /sbin/lilo and your set to go.