Require guidance for choosing postgraduation programme.

mechas

Hi guys,
I did B.Tech in Electrical and Electronics Engineering in 2009 and now I am going for post graduation. I have secured a good rank in GATE 2011 and want to go for M.Tech. But I am not yet sure about which course to take partially because I am not aware of what type of course content is involved. So I require some guidance regarding following points.

1) I am very much interested in research as a career. I have always been interested in both electrical (not power or generation but mainly electrical machines and devices), electronics(semiconductor devices, circuit design, robotics, optical electronics and lasers) and physics(especially related to cosmology, astrophysics, etc). I went for Electrical Engineering for graduation as I felt it would give me overview of the basics of most of these areas while I choose which I want to pursue as a career, while keeping other job opportunities in reach.
I have been an average student throughout graduation, but I have a clear grasp on the fundamentals. I have never been involved in any kind of research work, plus I have no idea about the future scope of any research field. So can anyone give me an idea about what research in any of these fields will be like and what are their career scope.

2) How much important is the institute with respect to course at postgrad level i.e. if it is a good idea to pursue a better programme from a less reputed institute?

3) I am also considering Ph.D and M.Sc(Research) along with M.Tech but mainly as a fallback option. Would it be a good idea if I chose one of them instead of M.Tech for a better course? Also since they are significantly longer courses, would it be worth it
(I am 24 years old)?