Changing the URL?

How do I change the URL from my temporary one (http://66.147.244.222/~plowingf) to my domain, Plowingforward.com?

I tried doing it once by going under settings and manually changing it, but that completely blocked me out of the back end. I have since properly transferred everything over from wordpress.com via BlueHost, but my url is still the obscure temporary one. Help please!