Do we vote on central banking policies directly? No, of course not. Does that mean nothing ever changes? No, of course not.
I'm not sure who, if Mitt Romney had won, he'd have named as Fed chair, but I suspect it wouldn't have been Janet Yellen. (Just like, had McCain won in 2008, we sure wouldn't have anything like the Affordable Care Act--which, flawed as it is, is a big improvement over the old status quo.)
That's how democratic access to money policy works; we vote, power realigns in accordance with our votes, and a few years down the road, we do it again.