Hi,
As I mentioned, I can only reccomend you to go for the LEVEL of course appropriate after 10th/12th grade, such as certificate, diploma or advanced diploma.
The selection of course discipline really depends on you, as to where your interest lies. How can I or anyone tell and select a course out such a diverse list of disciplines? I don't even know your background - Sci. Arts or Commerce! You may be interested in Engineering, Economics, Accounting or Marketing! It's really your decision to choose your field of studies.
What I can say is,
you MUST go for at-least a 2 years diploma or above course, so as to get you a proper profile and a solid foundation for your field of study since you have no primary degree of specialization and this will be your first major qualification and not to mention the 3 years post graduate work permit. Since I'm from an Economics/management background, I can suggest is if you are confused about the myriad disciplines to choose from, you can opt for a field that any one with any diverse background can opt to study for.. i.e BUSINESS.
Again, I suggest it will be best if you could complete your 12th grade with above average scores, you could directly apply to a Bachelor's degree level course.
Yes, on paper your dependent can go with you if you secure a study permit (although to confirm the exact procedures and rules you will need to check the CIC website), as long as you have and show the required money to support your dependent. Usually it's 11,000c$ (FOR SELF)+ 5,100$ (for an additional dependent) per year in QUEBEC.
http://www.cic.gc.ca/english/study/study-how-documents.asp