I Know there are 2 High Frequencies I do know of(135.6 and 123.925)What frequency covers north of those?
FL290 and above Montreal Center is basically divided in northern and southern sub units. The southern sub unit includes 135.600 which extends from overhead Montreal west to the Toronto FIR boundary, 123.925 extends overhead Montreal east to the Boston and Moncton FIR boundaries. North of 135.600 they use 127.875 which extends north about 150 miles. The same controller is usually working both the 135.600 and 127.875 sectors. I'm not sure what they use north of 123.925 ? It's not a very busy chunk of airspace.
North of 127.875 you are into Montreal's northern sub unit, which covers a huge chunk of airspace covering all of Northern Quebec, north of around 48 degrees north (48N), an area about as big as the eastern seaboard of the USA from Maine to Florida. There are about 19 high altitude frequencies used in this area, and the airspace will be divided up into sectors depending primarily on the flow/volume of north atlantic traffic. When traffic is light it's not uncommon for one controller to be working all 19 frequencies at once. You can find all the frequencies on this website:http://www.canairradio.com/qc.html
Secondly i know of 134.975,128.775,126.575,128.225/132.55,and 132.35(where are these frequency located in relation to each other and where do they cover?
FL280 and below Montreal is basically divided into east and west sub units. I'm not that familiar with the area east of Montreal, but to the west you have 128.775 which covers a corridor between Montreal and Ottawa extending to the Toronto FIR boundary. To the north of this you have 126.575, and to the south you have 134.975 which works YUL arrivals inbound via the Massena VOR/FRANX STAR, and extends south to the Boston FIR boundary. Often one controller will be working all 3 sectors/frequencies at once.
Like I hear montreal departures to the west get handed off to 128.775 after that sector which frequencies do they subsequently get handed off to going west bound to YYZ and americsan destinations before going high level
YUL departures westbound over the Ottawa area will check onto 128.775 as they climb out of around 11000 to 14000 feet on their way to 17000 feet, the controller will then clear them to FL280, and then when they get to around FL230 will hand them off to 135.600. If they are flight planned at FL280 and below the next frequency will be Toronto on 124.675, same with traffic on 135.600, gets handed off to Toronto on 124.675.