new knee pain

A couple of weeks ago i banged my knee cap on my desk at work.  It hurt at the time in a kind of 'whaked my funny bone' kind of way but after an hour or so i had forgotten about it.  I ran 2 x 10kms that week and forgot about banging my knee but on a 16 mile lsr that weekend i started to feel some pain.  that evening i was in quite alot of pain when my knee was flexed, so sitting on the sofa with feet on the floor infront of me.  it was fairly extreme and a little bruise had appeared,  the pain is on the upper medial side of my left knee, so at about 10 o'clock position if you were looking at my knee.  It can be sore to touch at times but the pain during and after a run is more like a tough peice of leather being stretched under my kneecap (if that makes sense)

i took a week of complete rest and then ran a steady 10k yesterday, i had some knee pain although not enough to stop me and have been nursing a little pain since.  i have been taking ibuprofen but doing little else.  i'm aware of RICE but havent really done it.

i have tried self diagnosis on the internet and the closest thing that described it is a medial meniscus tear however as far as i can tell this is fairly serious and requires surgery.  i certainly dont feel that my injury is that serious, does any body have any ideas as to what it could be or how to deal with it?

I'm 11 weeks away from my second marathon so i'm not fussed about taking large periods of time off from running.  do you think strapping and/or glucosamine sulphate could help?

Any advice would be great