Hey Vinit,
For taking admission for the computer science emgineering course(CSE) you have to qualify the Joint Entrance Exam (JEE).Your rank will decide your college for the course.You have to score good since your boards marks are not that good. Dont worry work hard and schedule your studies

Now coming to B.Tech CSE,it is a four year undergraduate degree programme consisting of 8 semesters all over. Nearly all engineering colleges provide placements and interships after completion of degree course and during pursuing of degree course respectively.

I will provide you with the best Engineering colleges in Pune

.College of Engineering
.Pune Institute of Computer Technology
.D. Y. Patil College of Engineering Akurdi
.MIT World Peace University
.Bharati Vidyapeeth University College of Engineering
.Maeer's MIT College of Engineering
.Progressive Education Society's Modern College of Engineering
.Sinhgad Academy of Engineering
.Symbiosis Institute of Technology

You can also try out for colleges which provide direct admissions for engineering courses by management quota.

Regards!