I switched over from environmental studies so I certainly think this is doable. I did have some coursework in the social sciences, and I had letter writers in anthropology, sociology, and history, decent GRE scores, and a 3.9 in my major. I also had a ton of science and non-anthropology related coursework, like calculus, physics, ecology, earth science, chemistry, animal behavior...I was really terrified that this was going to do me in, but I got accepted and funded for anthropology (much to my relief) and I'll be starting my program this fall, and I'm thrilled.
So...I think what you really need to do is demonstrate in your statement of purpose that you know enough about anthropology to be able to construct an interesting anthropological project - which it sounds like you've got the idea already! I've heard of people not getting in because their expertise isn't closely aligned enough, but it sounds like you're a strong applicant and you have a very anthropology-type project. Having gone to the country of interest I think is an awesome boost too. Also, I think it helps if you can tie in your political science expertise and how it motivated your interest in anthropology, or if you can talk about how anthropology contributes insight into what you're looking at. I really am a big fan of interdisciplinary work anyways. I say go for it Best of luck!