I need to get to the point where I can run 3200m in 12mins within 10 weeks from this week. QUOTE]
Are you going military or trying out for a SWAT team position?
I agree with evolution's recommendation of interval training, but I would go at it a bit differently.I would start out with two days of intervals, say Monday and Wednesday, and on Saturdays I would test myself in the 3200 meter run.
Push yourself in the intervals and use Saturday's run as an indicator of your progress.I would also gradually increase the distance of the intervals.For example:
First three weeks: 400 meter intervals
Second three weeks: 800 meter intervals
Third three weeks: 1600 meter intervals
10th week: no intervals
For the 400's, use these as a break in period.This is important, especially if you are new to running and have not built up an adequate aerobic base.Start out with 3 400's using 90 second rest intervals.Add one interval per week so you should be running at least 5 400's by the third week.60-75 seconds per 400 meter is a good time to shoot for.
For the 800's, again start out with 3 intervals and 90 second rest intervals and build up to 5 800's by the 6th week.A good time is 3 minutes or better per 800.
For the 1600's, run just 2 every week.This time, instead of increasing the volume, you are going to decrease the rest interval.Start out with 90 seconds rest on week 7, 60 seconds rest on week 8, and 30 seconds rest on week 9.6 minutes per 1600 is a very good time to strive for.
Abstaining from intervals in the 10th week is for recovery purposes, as interval training can be extremely demanding.Your 3200m run on that week is your only running session and should be a good indicator of the type of progress you have made.
If you follow this type of schedule, make sure you have a good pair of running shoes and a reliable stop watch.