Thanks for the advice everyone.
The first doctor told me that a knee support wouldn't help. However I'm still tempted to try one, it won't hurt anyway. And the foot soles might be a good idea.
thingstodo, thanks for the link. Although the page you linked too is about jumper's knee (patellar tendonitis). My problem is runner's knee, aka pattelofemoral pain syndrome (wonderful words, I know); and there is a page about it on this site:
http://www.med.umich.edu/1libr/guides/knee/kneeart.htm .
I tried some of this stuff before but I didn't help.. I might give it another shot, more seriously this time.