Help a newbie decide...please...

How long is the run in this "sprint"?

Ice is your friend.

That sounds like a super aggressive plan to begin with, and you don't want to risk further injury that may prevent you from competing altogether. I would just swim or bike instead. Perhaps later down the road, if you are completely recovered, you can sub in a 60 min run where you would normally swim or bike.

3.2 miles....

Who else thinks a 60 min run is aggressive for a sprint?

I think it depends on what want to achieve in the race. But if you're a "newbie" with modest goals, I think you'd do fine without it. 

Also the plan has me running only 2x per week...

A 60 minute training run is not aggressive for a sprint.

A 60 minute training run is aggressive for someone who has only been running for 4 weeks.

A 60 minute training run is way too aggressive for someone nursing a very recent achilles injury.

You asked: "How would you balance the need to run and the preservation of the body?" and the only honest answer is that your health comes first. There will be other races. Esp with the achilles - don't mess around with tempting a permanent injury.

Good luck with whatever you decide to do.

x2, don't tempt a permanent injury for 1 race.  there will be other races  Just swim and bike instead.  as long as you are getting your cardio in, it's not going to hurt you as bad as you might think

What is the duration of the other run on the plan?  I think 60 minutes is a long run for someone that is just starting out.  Take it easy, don't worry about missing the run, and heal from your injury. 

Increase the duration of your runs SLOWLY.  If the plan only has you running twice a week and one of the runs is 60 minutes maybe try tweaking the program a bit to fit your needs.  I think it took me at least 4 months to build up to a 60 minute run.

If you train through an injury it often takes much much longer to heal than if you stop and let it heal when it first occurs. Why do you think you got it in the first place? Maybe to much to soon?

Skip the run....

I've had achillies issues and when I start back running  I would run 10 minutes and see how my body responded to that. Never would I first run back go for an hour run. 

Always better to err on the side of caution. We do this for fun..be kind to your body. 

Aqua-JOG, get a float belt, get in the deep end of a pool and run, run your little heart out, you'll get about 65% of the cardio effect, and you will not do any more damage to a very very delicate and vital part of your body. You could do about 75% of your runs this way, and still have a good race.

P.S. Go see a real Doc or at least a P.T. for a more exact recovery plan. 

OK, guys run is OUT....  I will do something instead..  Bike, swim, lift what ever is avalaible.  My next scheduled run is next Wednesday for 45 min.. 

Thank you all for caring about me.... Seriously ,, Thanks...

Here are a few plans I found.  I'm trying the beginner duathlon.

http://www.team-magic.com/training_plans.htm

 Here is an 8 week Beginner Triathlon
http://www.team-magic.com/8_Week_Sprint_Tri_Plan.pdf

Even the intermediate plan doesn't have 60 min runs.

5K in 30 min, while not medal-worthy, is certainly a pretty good pace IMO, especially since this 'ol fart routinely runs close to this pace.  

X2 on what sty said above.

Be realistic, you have an injury, and an Achilles is not something to mess with.  It can lead to other issues such as calf and foot problems. 

Last year I left the tri pride home and did an Oly with no running for 6 weeks up to the event because of Plantar Fasciitis but I trained hard for the swim and bike and had a good race (all things considered) with a run/walk for the 6.2 miles.