I am a little confused about the training plan you are following, are you doing both at the same time?

Probably a bit more information on your level of fitness and previous running experience would help, but at first glance it looks like you might be trying to do to much. I do not know much about the injury you describe, but first of all I would make sure (probably consulting the ortho you mention or some other specialist) that it is not caused by overtraining.

Once this is settled, I would make sure that the injury is well cured before running at all (and running while on steroids does not sound like a good idea). I know how frustrating it can be to be sidetracked, but in the end you will be able to train more and better if you take it easy.

Concerning "getting back on track", one common convention is that you need about two weeks for every week that you have been off the tracks to recover your phisical shape. While this does not really have to hold I would advice to take it easy. Ideally you should regain your previous level of fitness and then continue the training plan were you left it, but as you are already using a "one size fits all" training plan, you can probably tinker with the formula (as Highdon himself suggests) and maybe skip some weeks if the training load is not increased drastically.

Finally, good luck with your race, I am sure you can get some positive (and more expert) feedback in this forum, whish you a speedy recuperation and many happy miles.

What's holding you back is how much your knee and hip bother you.  Assuming it is ITBS, you should acquaint yourself with the use of a foam roller.  You can find stuff on YouTube.  It sounds like you've only missed a week (or 2 or 3, it's not clear).  (Hopefully you passed the stone.  Been there, done that - no fun.  Pay great attention to hydration.)  If it's only one week, and your knee and hip are OK, pick up where you left off.  Three weeks - go back easy and take at least a week to get back into it.  You'll have to resume by feel in any case, because of the knee/hip.  Your main goal now is to get to the start line (reasonably) healthy.  So no "...need to hit it hard...".  Relax, take it easy, get back to training with no pain.  Hopefully you'll still have time to build a little distance..  When I ran my first half-marathon, my previous long run was a 10K, 10 months earlier.

Len