Lunch near Hyatt Regency
I really like Sur Bleury, a small café on Bleury south of René-Lévesque. Soup and sandwiches. About 5 mins from you hotel. Chinatown is also right nearby. I favor the Deer Garden on St-Laurent on the corner of René-Lévesque. Again, 5 mins from your hotel.
A little bit further but worth it is Titanic on St-Pierre which is the extension of de Bleury street in the Old City and on the way back, make a stop at Olive & Gourmando on St-Paul for sweets. Less than 15 mins from your hotel. Also in the old city there's le Cartet (McGill st.), Holder, Boris Bistrot (McGill st.) that quite good.