A tip I got for dealing with cat donations (which are even stinkier than dog's):
mix bicarbonate of soda with an equal volume of cornflour, add some essential oil - about half a teaspoonful for a cup of the mixture - and mix thoroughly (yes, the mixture will be dry. It's not a mistake). Work the mix into the affected area thoroughly, leave overnight, and vacuum up the following day.
Worked wonders on a very pongy piece of carpet. Good luck!