Sorry should have been more specific! We will be staying in old city with dinners at Joe Beef, Cochon and Kitchen Galerie. So either something near we we are staying or near any of the restaurants (sorry not so familiar with the neighborhoods). We don't have to be able to sit and are open to anything with either interesting cocktails or a good wine list.
re: mari mac
My favorite wine bar is the Pullman. Its not exactly near any of your restaurant but they have knowledgeable sommeliers and a good card featuring "taster's specials" which change every week (roughly 20$ for 3 2 ounces glass of wine)
There are tons of small bars and pubs near the Pied de Cochon (its the plateau after all) but I don't often go out on the plateau to drink so I have no favorites. Some people I know like the Billy Kun, other the Plan B, Les Verres Stérilisés, Else's but everyone has their favorite. I would recommend going on Mont-Royal and stopping where you feel most comfortable.
Near Joe Beef you have two main attractions: Burgundy Lion is a very good english pub and the Drinkerie Ste.Cunégonde is a cocktail place. They are both on Notre-Dame. The problem is that they are pretty popular so its jammed packed on weekends. Don't forget Joe has a good wine list on its own.
Just in case you want places in Old Montreal, which is really pleasant at this time of year to stroll around: Le bremner across from Bonsecours Marche, near main square in Old montreal has a bar and has reputation for good cocktails. I have only eaten there but good atmosphere even though in basement -sign outside only says Restaurant (chuck hughes 2nd resto in Old Montreal)
If you want to try some beers from Quebec microbreweries and fingerfood you would not be far from
Brasserie Les Soeurs Grises on McGill in Old Montreal (close to waterfront and silo)
Le Local restaurant in Old Montreal used to have wine tasting choice on Menu, you could also order lighter meal although some seemed to be just there for wines but havent been there recently, you would have to call to check if still an option