I haven't experienced this problem, but if you want a quick fix: PetSmart and I'm sure other pet stores have a spray that will encourage your dog not to like the area you spray.
http://www.petsmart.com/product/index.jsp?productId=2754400
That is the web site for one of them... people seemed to like it.
http://www.petsmart.com/product/index.jsp?productId=2754400
That is the web site for one of them... people seemed to like it.