Knee Replacement Surgery?

I had total knee replacement surgery on 6/6. I'm on Coumadin and take Percocet for the pain. I've a physical therapist coming to my home 3 times a week and my blood drawn weekly. It's been almost a month and I feel like I should be farther along in my recovery. I'm still using a walker. My ROM is going very well, or so says my therapist. The thing is, my foot is swollen like a balloon. It's very uncomfortable to elevate it above my heart for a long period of time. Any ideas? I only take my pain pills before therapy, therapist says I should take them more often. I know everyone's different, but I wonder if there's anyone out there with advice?