How can I transfer a vehicle title with co-buyer to only my name?

I have a car and the title is under my name and the co-buyer. The cobuyer has never made a payment etc. They were on the loan for a better APR. Now the co-buyer is being unhelpful to transfer the title fully into my name. It is in the state of Virginia and is titled as "and" not "or". Do I have any options (ie court etc) or just hope they stop messing around? With it titled as it is I can't do anything with the car now or in the future. Can't sell it, trade it in, even if it's totaled I can't sign it over to my insurance company? Suggestions?