US Immigration from Canada

Hello everyone, I am a Chinese citizen waiting for the CR petition in Canada. My husband is U.S. citizen. I am legally staying in Canada on a work permit. I am still waiting for the NOA 2; meanwhile, I want to know, since I am a Chinese citizen (no PR in Canada), could I have the interview in Canada? (Staying in Canada is better for me to keep contact with my husband!)

If not, do I have to going back to China to have the medical examination and interview?

I received packet 4, where I have to make appointment for medical and interview. My issue is, there's only 5 approved physicians listed(on the gov website) for ALL OF CANADA, and the closest one to me is all the way in Surrey BC, while I'm in Alberta. And the interview is all the way in Montreal.... Is there anything closer that I'm missing? Is there anything I can do to make this easier? Or do I just have to travel across the country...?

Also, for the medical, what kind of cost am I looking at?