just my advice- but dump the heart-rate monitor. I've found for myself at least that not only are they a pain in the ass to wear- but the readings can be inncacurate and misleading. If the weather is off, you may be working too hard for a certain heart rate, and this works the other way around too.
run by feel! Feel good? push the pace a little. Tired and weak? keep it easy and slow.
Keep up a weekly long run.