I am confused, why don't you just use an exchange to buy coins at the going rate? It just takes a second to sign up and do a sell order.
This:
you can just use shapeshift.io
One don't even need to make an account and it's instant, just enter your Bitcoin wallet address in the receiving field click start and you'll see a dogecoin deposit address and you only have to send dogecoin to that address and you'll get bitcoin to your bitcoin address within minutes.