Export Multiple tables of SQl Serve rt o multiple Sheets of Single Excel File

Hi
1) i want to Export Multiple tables of SQl Servet to multiple Sheets of Single Excel File.
2) i am able to Export using string Writer but it only writes on first sheet. i can write multiple tables on 1 sheet but i want multiple tables on multiple sheets.
3) can't use following
    OpenSource.
   MS Office librar.
Thank U