MSW to Sociology PhD

[Webster]

Hey all,

I am in a bit of a pickle. I am a Speech Communications major and recently decide I wanted to pursue Sociology, eventually PhD. My question is, what are my chances of being accepted into a fairly good PhD program with a Masters in Social Work and no undergrad in Sociology? It is easier for me to get into a MSW program than a MA Sociology, because of my undergrad major and lack of Sociology degree. Would you recommend going straight for the MA in Sociology instead, even if it is at a not so well known program? (I've looked at Northern Colorado, Northern Arizona, NM State, Wisconsin-Milwaukee, UMBC, etc.) Thanks!