jqplot and php

quick few quiries if anyone can help:

im wanting to pull information from the web server and post it into nice graphs

so far ive managed to pull the average load.
but
how would i pull cpu details in php?
how would i pull ram information in php?


and how would i then plot this in a graph
like the server load graph below

http://www.keenthemes.com/preview/conquer/index.html


any idea?

thanks in advance