When you open up the memory port on the bottom of your laptop, is the memory slot filled or empty?
That 128MB you have might be fixed. (Soldered on chips as opposed to a SODIMM module).
If that is the case you can only add the # of modules you have free (probably just 1).
If it's removable you can obviously populate the # of slots open w/ SODIMMs.
RAWR!