Sorry that you still haven't heard from her. You can continue NC, or take a more pro-active approach to trying to get her back. I can't tell you which to take. When does it get easier? With time, and the decision for you to let her go for good. That should be when it starts getting easier. I don't think it ever will truly heal, unless the relationship was bad. Some people need more time than others, so consider that as well.
Sometimes NC is all it takes to get someone back, it makes them realize what you were to them, other times NC makes them think you do not care anymore and so forth. It really depends on your situation and the person involved. We all know that the main purpose for NC is not for getting an ex back, but it does play a part in it. Do what you need feel you need to do. Sometimes they need a little nudge, just don't over do it. Space out your contact attempts, at least a week apart, if you get no response. Make sure you leave a message; something friendly, vague, and will pique her interest enough to contact you, or something that brings back a good memory when you two were together. You should limit how many times you are really willing to try before giving up as well. If they never respond, then you have your answer. Just make sure you have the correct contact info.