If you can't hit terminal gravity with your current yeast, I've had good luck re-krausening by building up a large starter (say 4L for 5 gallons), chilling, decanting, re-invigorating in a smaller starter (say 800mL), then pitching this active yeast.
Using this method, I was able to take a Barley Wine with OG=1.111 down to terminal gravity after it stopped in the mid 30s.
Cheers!