Harv's Air is a good choice. My son is currently enrolled there taking his PPL.
Harv's has two operations, one in Steinbach and one at St. Andrew's Airport, 15 minutes north of Winnipeg. The facilities at St. Andrew's are excellent, as they took them over from the Winnipeg Flying Club several years ago. The quality of instruction and the level of professionalism is top-notch. My son's first instructor was hired away last summer to train the Canadian military pilots at Portage La Prairie. Training there in July could be problematic, as they host about 20 Air Cadets, so getting an instructor and/or an airplane during that month alone is difficult. They generally finish by the first week of August.
There is absolutely no reason to not start training in the winter months. Operations are necessarily more difficult, but the weather is usually favourable to training, with most days being VFR. TRaining aircraft are usually kept in the large hangar overnight.
Regarding study materials, you might consider signing up for the on-line training some time in advance of your arrival, in order that you get a handle on several of the basics across the discipline, including theory of flight, aviation meteorology, navigation etc. The on-line training is accredited, and can be used to minimize the actual time required to be spent in a classroom or alternatively, with an instructor one-on-one.
Without any doubt, the best way to keep the costs down is to dedicate yourself fully to the training for a fixed period of time, and stick with one instructor only. Two lessons per day, six or seven days a week, until complete. Large gaps between training sessions means that a lot of time is spent, with the meter running, going back over previous lessons.
One other thing. Get your medical up front by a medical practitioner that will be recognized by Transport Canada. No point in getting here and starting flying only to find out that you have some previously unknown medical impairment that would preclude you from being able to pursue your chosen goals.