In order to be fairly successful with pitching a new yeast to finish the job, you really have to make a small starter and pitch it at high krausen. If you used dry yeast and simply rehydrated, then those yeasties really won't have much of a shot at finishing out your saison properly. I would say you may just have to call it done and package it. If you really want to drop those extra few points, then you could always pitch some brettanomyces (either Brett B. or L, I like) into your brew to finish the job and add some interesting rustic aromas and flavors. But that is a whole new ball of wax if you have never used wild yeast or bacteria before. You will need to keep separate plastic tubing/hoses/airlocks etc. for anything that comes in contact with that beer.
Sorry, just saw that you made a starter for the champagne yeast. Sounds like your brew is done. At 1.011 your saison will taste awesome, just be sure to carbonate high to get it taste drier.