Hey Mel! Good luck with your training for your du and tri! Very exciting stuff.
I would also encourage you to start doing at least one brick a week, once you feel like your have your running up to par (for your goals). Especially with the du... you are going to need to train your legs to feel good going from bike to run.
Keep us posted on your training and progress! And keep at the running... sooner than you think... you will be running the entire distance!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"