The only possible way to increase the intelligence of the machines any farther will be to begin converting all of the matter and energy in the Universe into similar massive computers. A.I.s will radiate outward from Earth, first into the Solar System and then out into interstellar space, then galaxies in all directions, utilizing starships that will be Von Neumann probes with nanobot crews, breaking down whole planets, stars, moons, and meteoroids and reassembling them into computers. This, in effect, will "wake up" the Universe as all the inanimate "dumb" matter (rocks, dust, gases, etc.) will be converted into structured matter capable of supporting life (albeit synthetic life).
Kurzweil, Ray. 2005. The singularity is near: when humans transcend biology. New York: Viking.