Jen. You need to really ramp up your riding now. LONG rides every weekend (like 100miles). Experiment with nutrition, what works for you and what does not
A full IM is totally about nutrition, you need to be able to get off the bike without any depletion of glycogen, or you will blow up on the run. Your swims need to be long as well. By ramping up the swims and rides, you will increase endurance without overstressing your joints and tendons.