extrusion help required

I am trying to extrude certain parts of my geometry, but not sure where to start - I was hoping someone could point me in the right direction! I'd like to extrude small sections  like the ones highlighted - I have started by exploding the geometry but that has brought my computer to an absolute crawl. Any advice/help gratefully received - is this something that would be more easily manipulated inside rhino perhaps? 

Many thanks in advance, natasha