From what I've just recently learned about upgrading a notebook is, really only the memory and hard drive are things you should upgrade in them. The rest is either far to expensive or just to expensive to have installed.
I wanted my notebook to be faster and they told me the main thing that will determine that is the processor. Yet they said if you had the money to do upgrade that then just go for a new notebook.
Something cheaper that they said would show an improvement was memory though, so I upgraded from 512 to 2 gbs of memory. Which I noticed a huge difference in performance, though yours only goes to 512 so I'm not sure. What OS does it use?
I know a bit more about software than hardware