To my knowledge Hemisphair have closed their doors over 2 years ago.
However, there's Dorval Aviation operating a few FBO's next to where Hemisphair used to be. you can try their website at
www.dorvalaviation.com
If you own a car or other means of transportation you could also try Laurentide Aviation who are located at Cedars which is to the south-west of Montreal. Their website is currently down but you can try calling them at 514-875-6669 for information.
Other schools would be located at St-Hubert airport. However, there seems to be a constant change of schools there. Montreal Flying Club has moved and melted into Laurentide. Pro Aviation went out of business. I figure Cargair is still left as well as another school I heard of who have opened for business recently with some of Pro Aviation's planes.
Hope this helps.