M.Sc Computer Science

Yes, why not. You've studied all those subjects. So, you can sure chose them as mainstream.

Yes, after completion of BCA, you can join M.Sc Computer. But you need to find the cutoff for this college because your BCA marks are low.

When you study abroad, all Masters are specialised programme not as general computer science. Normally Masters in computer Science is a conversion programme for non-computer UG people to come to IT field. Hence, first, you decide what you are going to study and then look for universities. RMIT is one if the top universities. See the website and see the courses offered. Also, be aware of the cost. It will cost you 30 to 40 Lacs in Australia. You can do one year master in UK for just less than 29 Lacs.

SVUCET Question & Sample Papers 2018
Download previous year question papers and sample papers of SVUCET 2018 for your exam practice at the link provided below. You can download all last years' SVUCET exam question papers and sample papers free of cost. You can also download preparation guides for SVUCET designed by Shiksha experts. https://www.shiksha.com/university/sri-venkateswara-university/exams/svucet/question-papers.

Please check for your eligibility to pursue this course from the criteria mentioned below:
Eligibility for M.Sc. Computer Science:
The basic eligibility for M.Sc. Computer Science course has been mentioned below. Candidates must have completed graduation in B.Sc. (H) Computer Science or B.Sc. Applied Physical Sciences with Mathematics and Computer Science
Candidates who have completed B.Sc. (General) Mathematical Sciences, (10+2+3 scheme) with Mathematics and Computer Science are also eligible to apply. Regards.

Accordingly, you are not eligible for M.Sc CS after B.Sc PCM because for M.Sc CS admissions the candidate must have be a graduate from B.Sc computer science or technology. If you are interested in technological field then you can opt MCA.

Please check for your eligibility to apply for KTET from the criteria mentioned at the link provided below:
https://www.shiksha.com/teaching-education/exams/ktet.

You can apply for NIT Trichy or BIT Mesra.