Hi Jagrati,
It may be true that syllabus is vast, but one can study thoroughly to have a crack at it. First of all get the following books.
1. GRE subject test book from ARCO publications (its abt computer science) Goyal Saab is one distributor of this book.
2. then have following classics below
* OPERATING SYSTEM - SILBERSCHATZ GALVIN
* COMPUTER NETWORKS - ANDREW S. TANENBAUM
* COMPILERS - J.J. DONOVON, AHO & ULLMAN
* LANGUAGE & AUTOMATA - AHO & ULLMAN
* DIGITAL LOGIC - MALVINO LEACH, R.P JAIN
* MATHEMATICS FOUNDATION - ANY INTEGRAL & DIFFERENTIAL BOOK
* C - KERNIGHAN & RITCHIE
* C++ - BJARNE STROUSTRUP
* DATA STRUCTURES - SARTAJ SAHNI, TREMBLEY SORENSON
* DISCRETE MATHEMATICS - TREMBLEY MANOHAR, C.L. LIU
* ARCHITECTURE - LIU GIBSON OR ANY OTHER x86 BOOK
these are just books, besides net is good source for problems that are classical. and one thing thats most important is - PLAN of ACTION. how many hours u study and scheduling for each of these topics.
I am planning to start soon. by email address is : kirti_intellix@yahoo.com, if u would like to synchronize with me along for studies, u can mail me.
All the best.
Kirti