Homebrew PCBs

Hi all.
  Does anyone know how to make Eagle make bigger vias? Someone 
pointed out a ULP script within Eacgle that allows you to chang the 
diameter of the insides of vias, but I need to change the outside 
diameters.  (probably right in front of me).
  Also, I have an RF project that I'm building, and I need the bottom 
side of the board to be all copper ground plane, except where traces 
run.  Does anyone know how to get Eagle to do this?

Thanks

Josh