Sandeep I am sorry to say but with your 1501 SC rank and 27000 GMR in WBJEE 2018 exam forget about CSE or IT department branch in the government college, you will not be able to get any branch in any of the top government colleges. 

You can check the last 2-year cut-off of all the branches in the top government colleges by going through the link below (cut-off rank even under the SC category is given as the GMR so check the cut-off with your 27000 rank):

• https://collegedunia.com/exams/wbjee/cutoff

You can get admission in some of the private colleges like:

• Abacus Institute Of Engineering & Management, Mogra, Hooghly
• Academy Of Technology, Adisaptagram, Hooghly
• Haldia Institute of Technology, Haldia 

Feel free to ask if you have any more queries. All the best!!