Hello~I am sorry you are having such pain in your knee, that is no fun. I highly recommend seeing a chiropractor, when I have had knee pain, he has helped it immensely, He/she will take x-rays of the area, study them and then go over their findings. After a few treatments you knee should start feeling lots better.
The reason I am suggesting a chiropractor is because when certain vertebrae in your lower back are out of alignment, the pain it causes can actually radiate down the leg to the hip and knee, when the pressure is alleviated, then the pain normally stops. The chiro will also no doubt give you some special stretching exercises specifically to help the knee, hips and legs.
I hope you can get some relief soon, a year is a long time to be in pain.