Ironman in 2013

My feedback is that if you'd like to be a successful triathlete, you have to train all three events, and do them all together in races. 

Your plan below doesn't really set you up for triathlon success because it's way too run focused, has minimal cycling, and you don't start swimming for 9 more months.  It emphasizes your strength and doesn't work on your weaknesses.  The short answer to "How do I train for an IM" is "swim, bike, and run lots".

You should start swimming now.  Swimming is a technique sport, and you may get it in 3 weeks, or you may take a year.  Cut 2 (or all 3) of those strength/core workouts and swim instead. 

Start biking now.  Cut one of your weekly runs, turn it into a bike interval for 2x cycling per week. 

In 2012, Sign up for some sprint triathlons in April or May.  The half marathon in July is fine  You don't need a bike race - bike races are entirely different beasts than IM cycling.  Sign up for a September Olympic distance race.  You don't need weight training.  Swim bike run lots.

In 2013, skip the marathon in February. You don't need it.  Instead, sign up for April half Ironman. 

if you do all that, you should be set up for IM in late 2013, and do well.  Good luck!

I agree - get the swimming going early (and get the coach earlier, too) so you and your coach can assess your current level and progress while you still have time to fix things.

Bike - you really can't put too much time in.  Don't sacrifice your swimming, but otherwise bike as much as you can.  I'd shoot for 3-4x per week but this is where you should start evaluating a training plan.  There are plenty of books (Be Iron Fit is one), or you could work with a coach.  Either way, it will give you an idea of the type of schedule you'll be sticking to.

Also, keep in mind IM races start registration a full year in advance.  And many of them sell out within minutes.  So if you have a specific race in mind, you should plan to register on race day in 2012.

You are putting the cart before the horse -- It isn't that easy to even get into an Ironman.  Unless you are flexible and are planning to do Ironman Lousiville.  Ironman Wisconsin and Arizona (the two late season US races) usually fill within minutes of opening.

With that being said - scrap the full marathon for sure and plan to spend the most time working on your weakness - ie swimming.  Start swimming now, join a masters swim team and swim swim swim. Then bike bike bike.  People greatly overestimate using the run - the majority of people doing Ironman are not even running and yet when they train they train to run these 7:30 pace miles that just doesn't happen.  Without tons of biking and tons of swimming your marathon run will just turn into the longest walkathon of you life no matter if you are 2:30 marathoner or a 4:00 marathoner.

Lastly I see a focus on going straight to the Ironman.  I don't like this approach - this summer you should be doing some triathlons - sprint and Olympics, maybe even a half.  Next summer you should do some more halfs in preparation for a full.

If you haven't already, I'd suggest that you look at some of the training programs available on the site here.  It will give you a good sense of the balanced and extensive workload recommended to prepare yourself for an IM.  That is the real IM challenge.  The months of big volume consistant training.

For starters, you might take an Olympic or HIM plan and modify it to your strengths, weeknesses, preferences, etc. and start getting a feel for the routine.  I'd do that this year and than start looking at following an IM plan next year.

Start swimming 2-3 times a week. The goal is to build technique to the point you can swim 4k without feeling tired.
Ride 2-3 times a week with one long ride each week.  The goal being to feel freaky fresh after being on the bike for 5 hours.
Run easy sometimes hard but mostly easy.  You've already experienced the mental side of 26.2. Running 26 during IM training has a negative net effect in that it takes you longer to recover from the distance than the amount of physical adaptation benefits.

As you build towards IM distance experience the trials of the sport at a shorter distance.  Getting kicked in the face, losing your goggles and swallowing a bunch of water in a 400 yard swim seems very dramatic but can be easily recovered from.  Once it happens to you it becomes 'no big deal', and will not negatively effect you on your IM debut.  There is a certain knack to swimming with 2000+ swimmers all turning around the same buoy.

Going out on the bike or messing up your nutrition and hydration plans can happen on the short course and be something that slows you down a little, but these kinds of mistakes at IM distance can spoil 'your' day. 

Beside Sprints and Oly's are a heck of a lot of fun and a lot easier to get into.
Cheers.