As per my understanding,
You have two files. One is Tabulated another is also Tabulated (as per my assumption)
but still they have some miss matches so you need to map one to another.
The source file is tab delimited (as you said) now rename it to CSV extract it using OLEDB, then you will get DataTable and the same way you will able to insert selected columns to destination file ( as Its also assumed as Tab delimited ).
For further classification Read
Insert Data Using OLEDB