Diploma

For B.Tech, you need to clear 10+2 from a recognised board. If you have passed 10+2, then yes, you can apply for B.Tech in computer Science.

Hi Prathik, This may help you all the best:-
https://www.shiksha.com/college/vjti-Mumbai-veermata-jijabai-technological-institute-matunga-east-19301/admission.

Hi Helal,
The dates will be declared in the month of July 2019. Rest, this may help you:
https://www.shiksha.com/university/jamia-millia-islamia-jmi/jamia-millia-islamia-entrance-exam-answer-key

yeah you can get the admission after completing your diploma.

The fee structure depends on the institute the fee starts from 10,000 and up to 8 Lacs.

Hello S Kumar, I am attaching a link that will give you all the required information about top 10 and more colleges in India for electrical engineering courses. https://www.shiksha.com/b-tech/ranking/top-electrical-engineering-colleges-in-india/47-2-0-0-0
Best wishes to you.

Yes, you can pursue this. You need to either look for CCSU or IGNOU other than regular universities. But now only the first 2 universities would be accepting admissions as the admission process of most of the universities has been completed.