Technically if you are sober now there is no need to pump and dump unless its for comfort/supply reasons. Alcohol in BM is the same as in your blood, it doesnt stay there and is processed. Eg if you dont have any alcohol left in your bloodstream then it wont be in your milk either. If you pump now and there is still alcohol in your blood stream technically the new milk could have alcohol in it again.
http://babyparenting.about.com/od/breastfeeding/f/pumpdump.htm
If it makes you feel happier, by all means go ahead and pump. But if you feel sober now dont be worrying that its 'stored' in your boobs - its not! A rough guide for how the body processes alcohol is 1 unit per hr on ave. Its best to do this from you stopped drinking to be sure. Eg if you had no more than 12/13 units it will certainly be out of your system by now.