Hey as mentioned by you that you know Java Basics...so I wont tell you to go for a Java Beginners book.....
Hence you can start off with K&B right away...as this book will help you a lot for SCJP preparation....
Once you are finished reading this book...try giving mock exams...there are lots of mock exams available in this forum as well...and there are some others also...so give some hands on on them....
Well as you are a College student then according to me
you should atleast give 2 hrs everyday ...but well it would also depend when are you giving the exam...if you are giving it after 2-3 months then 2 hrs everyday will do...
So just hope for the best and do well......both in your final year and SCJP...
Take Care