the first post doesn't say your total mileage and I read the 10-15 miles more as meaning that you run only 10-15 miles over and above the track work per week. it also doesn't state your 5k time or any other race times. so just come out with all that stuff first and then you'll get better answers.
The 1k's are a bit harder, obviously, but from my experience, the 1k and lower stuff is of less help for 5k and above than 1200m-2 mile repeats. 1k and down for me at least helps with the mile, but not much with longer stuff. in fact I can always run the 1k and down to 400m's between 3k and mile pace, with 200m rest, while not being able to run comparable quality performances at 5k. do the longer repeats, get the mileage up to 80 (not really that time consuming), and make sure to do the long tempos. Don't listen to the guy who advised 5k-10k tempos at 6:00/mile or a bit slower (90-92s/lap). You should be able to do tempos at that distance in 5:40-5:50 pace, at least.