BCA

If you want to study abroad, you can opt for Master of Computer Science in the US or go for M.Sc in IT in India.

College change or university change after first year is completely dependent on college and university norms, some university allow it and some won't plus you need to have good scores in first year to apply for the same. For further details contact the college authorities.

Please elaborate your question for better assistance, what exactly do you mean by open admission?

Hi Ajaydeep, sorry to say but 56%is very poor for Canada and then you have a three year degree course which is not accepted by many universities in Canada. You can check courses of your interest (what to study is your choice, you should know what your interest are) in colleges like Durham, Fanshawe, Alonquin etc ,these colleges fall under the SPP and may consider your grades.

Hello,
In terms of recognition and post-study work options, I would suggest either Canada or Germany will be the best option.

https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/it-software/colleges/bca-colleges-kolkata&ved=0ahUKEwiDvqys_urVAhVDsI8KHT-rBrwQFghdMAE&usg=AFQjCNFDnFFFH4v9UZAb9TZMTYh0-6v6wQ
The above colleges are best according to the rankings, please check and select the best college.

I can see that you are not ready for Masters abroad as of now. You must try to work for a couple of years at a good form where you will gain relevant work experience and develop your personality and skills. Then after if you wish, you can go for an MBA.