My interest is working in office administration or computer..while i had worked in business company for shortwhile i loved the job. Which subject will be best for me to start my career in future and give me good income too.

You should look at taking training either as an administrative assistant, or as an executive assistant. I have seen many jobs in these areas, but not have seen too many in a lot of other office positions as most of the elementary office jobs are being phased out, and they are going to the more "senior" sort of roles. I hope that this helps you.

Speak to an academic adviser at your college or University you'll be attending since they'll know what your looking for.