Moving it to secondary is not going to help your FG... If it were me, I would boil up .25 - .5 lb of sugar and some yeast nutrient in 8oz of water, cool it, and add it to the fermenter. It should take back off, and hopefully take some of the residual sugars with it. 75 should be plenty warm, but this is a saison, so if you can get it up to 80, go for it. I just did this with an IPA that I ended up mashing a little high, and I got 4 points after it being stuck at 1.018 for 2 weeks.
Did you make a starter for the saison?