Very sorry to hear about your injury. I had one last year. I am not a doctor so just relating my experience. Be careful, you get a stress fracture from training too hard too fast and the tendency is for someone to try to get back into training too quickly. While being sidelined due to stress fracture sucks, it can easily get worse by not giving it time to heal. I was 'cleared' to bike but that hurt it as well so just did not do any running or biking for 2-3 months. Had a shoulder injury at the same time so I was pretty much out of commission.

If you search on Google and the other forums for stress fracture stuff you will see stories of people who reinjured and could not bike/run for much longer periods of time. I let pain be my guide for the most part. I am now getting back into shape, but using a much less aggressive running schedule. I am also focusing on losing weight as that obviously contributes to over stressing the bones.

Also be careful about the race causing you to push your self into worse injury. My injury caused me to miss a marathon that I had already purchased tickets for including the family, lost almost 2 thousand dollars. Yeah, it sucked. Wanted to punch the dr. office's walls in when I got the diagnoses as I knew what it meant right away. Months and months of training down the tube.

You can also try elliptical trainers, they were too much for me at first but that is what I used after a couple months to start getting back into training. I was very skittish about high impact as I did not want to reinjure and go through all that again. Ug.

There is also water running, where you put on some fancy flotation stuff and run in the deep end. I never got around to this but have heard of good benefits, though mind numbingly boring.

Good luck.

Tommy