How long to recover from injury?

After weeks (about 5) i'm still working on getting my leg back together so that I can run again. A gentle trial run of 3 miles (3 weeks ago) proved that the healing process was nowhere near complete. I stopped at 2.5 and and nursed myself back home. It's difficult to know how to progress from here. So for the record, i'm doing regular 1 mile runs. 3 maybe 4 a week. At some point, hopefully, when I can go 1 mile without thinking to much about any unwanted sensation from my knee then i'll move it up a little bit. Maybe 1.5 miles. Today I think I hit the 1 mile mark without much discomfort, so i'll try a couple more times and progress from there. I'm also interested in the article in Runner's World about elite sports people recovering from injury and how much simpler it is for them. Need to go and find the magazine though.