do wind sprints: this how I kept my 3 mile run time in the 18-20 minute range when I was in
do a slow 400 meter jog to warm up
from there
Run 200 meters as fast as you can
walk 200 meters at a brisk pace
repeat that until you feel like you are going to puke
when you can do about 8-10 cycles of that with out puking
increase the distance to 400 meters walk/run
when you can do that for 8-10 cycles without puking decrease the walk distance between each 400 meter run to 200 meters
eventually you should try to get to 8-10 800 meter sprints with a 200 meter walk distance beween each sprint
This is not something you would want to do every day, substitute it for one of your endurance runs twice a week. You are probably not going to get past 1 or 2 400 meter run/walks before you go into boot camp, but you will be a lot better off than you are now.