calf injury need training advice

Can anyone help? I have been training for the FLM and have picked up an injury to my calf/ achillies after running 15miles in the first week of March, since then I have had sports massage and RICE but consiquently have missed out on being able to run the long distances that i should have been running this month. This week was my first run after the injury and i managed a slow 10 miles on a treadmill before my calf started to niggle me again. Can anyone advise me on what to do training wise as i don't have long before the marathon. Originaly i was aiming for a sub 4hrs, but now realisticaly would love to just be able to cross the finish line running.  

Can you get access to a cross trainer machine in a gym ? Mind numbingly dull, but it's low impact. Or cycling, keep the cardio fitness levels, although you will lose some of the leg strength you develop through your LSRs.
I'm 38 days out from my marathon and my calf blew up again last night big time, so it's RICE+cycling+swimming for me for 3-4 weeks at least.

thanks for the advice, sorry to hear about your calf, looks like i'm just going to have to settle for a get me round pace. cheers