Colleges in Andhra Pradesh

I think there is a mistake in your question.
Because GATE is meant for Post-Graduation courses but it can't make you to get into B.Tech
First of all, you have to complete your B.Tech to be eligible for the GATE.
But, if you want to join in B.Tech CSE in GITAM, you have to appear for GAT entrance exam conducted by GITAM University and the cut-off will be changing every year based on the number of applicants and GAT score around 300+ out of 400 can easily assure your admission into CSE even in Vizag campus.
Even if you are not able to score the cut-off don't be disappointed because later, if you contact to take admissions desk of GITAM, you can get a seat if the seats were still vacant.
All the best.

Please check for your eligibility to appear for the APSET entrance exam from the criteria mentioned below. APSET 2018 Eligibility:
APSET 2018 eligibility criteria which aspirants need to fulfil in order to be eligible to appear for the entrance exam is as mentioned below:
Candidates should have secured a minimum of 55% marks (without rounding off) in their Master's degree or equivalent exam from any university/college that is recognised by the UGC. Aspirants belonging to the reserved categories such as OBC (Non-Creamy Layer)/SC/ST/PwD are eligible to apply if they have secured a minimum of 50% aggregate in their Master's degree or equivalent exam. Aspirants who are appearing for their Master's degree final year exam and whose exam result is awaited can also apply for APSET exam. But such aspirants will be offered provisional admission and they need to submit their exam result details at the time of admission. Candidates who possess a Ph.D. degree and who have completed their Master's level examination by September 19, 1991 (irrespective of date when the result is declared) will be eligible for 5% relaxation in aggregate marks (that is, from 55% to 50%) for appearing in APSET exam. The official website informs that, Candidates are advised to appear in the subject of their post-graduation only. The candidates, whose post-graduation subject is not covered in the list of subjects may appear in a related subject. Age Limit: There is no upper age limit for candidates applying for the post of Assistant Professor.