I don't have any advise to offer but am also a non-anthro background (currently a lawyer). I always wanted to be an archaeologist when I was younger but went the "practical" route and studied business then law (and hate it.) I plan to take all the intro courses this summer at a community college, then apply to a local MA program. Just from my online researach, I think this will help chances of later applying to Phd programs.
One thing I have found (by actually calling phd programs at the UCs here) is that some of them will give you "credit" for your MA, or part of it, while others will essentially make you repeat whatever courses you took for the MA, because they expect you to obtain your MA on the way to the phd while in their program. That makes this a tough decision, because the MA can therefore set you back a couple of years, depending on which program you end up at. Overall, for me without a relevant background, I think this will be worth it.