Such jobs are my daily practice. I plan to complete the project via writing an Excel macro (which Excel version doyou prefer?) contained in a separate XLS (or XLSM) file.
This approach makes further use of the macro very convenient by offering usual Open file dialog to identify the current input CSV file.
Further use of macros, fixing of bugs and minor changes are included in the bid without any additional fees.
If you send me a sample file, I'm ready to create a draft pilot in order to make sure everything is rightly understood.
Regards!