Osteo-arthritis knee pain- is there anything I can do?

starr68

I recently started walking regularly during my lunch break. Our company has given us all pedometers (they sync with MapMyWalk and Myfitnesspal) and it has motivated a lot of us to start walking. We are doing a virtual walk across Canada and have walked about 700 kms in total so far this month (as a group).
My dilemma is that my osteo-arthrits kicks in in my knee and I am in so much pain by about 10-15 minutes into the walk. I push through and do about 25 mins (about 3200 steps or 2km) but I pay for it after. I have taken an ice pack to work with me and put it on my knee while I am eating. I also take Advil but even now, 6 hours later, my knee is so sore that I cannot bend it properly.
I don't want to stop walking as I am really enjoying it when the pain isn't making it tough. I am wondering if anyone has any remedies or answers that may help me deal with the pain and swelling other than what I am doing???
Looking forward to all information available!