FOR APTITUDE :go and download paper from campus gate . definitely u will clear aptitude.
and practice solved question from RS Aggrawal .
otherwise fast track for mathematics is also good .
FOR INTERVIEW :just go through ur core subjects . they will ask u question from ur subject. and cram few programs of C language. and if u are not good in cramming the program .tell them that u are not good in mugging up the programs . so, that they will ask u to explain the program .
GOOD LUCK!!