MCA

Yes, you've done your B.Sc with computer science then you are eligible for MCA. This year, govt. universities' admissions for MCA were closed but there are many private colleges where admission is going on.

No, try for M.Tech instead of MCA, which (MCA) at times is considered equivalent to B.Tech.

IMS-Noida is a very good college for BCA.
Many companies visit their campus every year.
You just need to focus on your studies and maintain a good academics in all semesters.
Placement totally depends on the student.
So, be ready for the interview to face any type of question.
Good luck!

You can go for:-
Amity
IET
Babu Banaersi Das, etc.

The fee for MCA structure is about 1 Lakh 80 Thousand for three years!

MS in computer science from abroad like US, UK is better option. Actually if you compare it will be financially equivalent to pursue MBA from top institutes of India or MS from US.

You are a BCA student. If you are interested coding, progamming, etc. then you can go for MCA. If you are interested in the management field, go for MBA (IT).

For MCA admission, the first preference is given to ranking in entrance exams i.e. PGCET or KMAT. There are some colleges offering MCA on merit basis. You can try in BITS. Else Pune or Bangalore is a good option.

Check out the link given below:
http://entrance-exam.net/forum/general-discussion/possible-join-mca-after-doing-diploma-computer-engineering-1032741.html