You may not have the mounting holes for the top L brackets, but they are easy to drill. Your monitor, if it is a Sanyo EZV or a Sharp XM-2001N should have the correct tabs on it for mounting it vertical.
So, all you should need is the L Brackets, horizontal cross bar and the lower monitor mount.
MONMNTN, MONLBRKTSN and a MONXBARN should do it.
Best,
- Mike -