Have a look at this site: http://www.marathontrainingplans.co.uk/
Good overall advice for marathons include nutrition, training plans, stretching etc
All the best!
Have a look at this page: training for a 1/2 marathon
Seeing as you are already a runner, you should be able to be ready enough within 10 weeks, as long as you train hard enough.
Have a quick read through this http://www.marathontrainingplans.co.uk/5k-10k-training/
Not sure who's a beginner and who's a more advanced runner but just thought I would share this site on training for various types of races (marathon, half marathon, 5K & 10K).
Good general info for amateur runners.
All the best
Check this link out: 5K/10K training as well as the marathon training site.
It should give you a good idea as to what you can achieve, and how much training is required
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