The trick with this yeast is to throw enough at your beer to allow it to finish in 3-4 days. SO... Warm it up to about 72 and rouse the yeast (without splashing) every couple of days for another week. That's about all you'll get out of it. I calculate that you should only expect 1.016-18 with that amount of yeast in a 1.065SG beer. What temp did you mash at and how much crystal malt did you have in your recipe?