Hi Ianjusto,
Let me get this straight.
You need a table that is automatically inserted "@" before the Twitter username? And this spreadsheet is saved directly as CSV, so you vizualize directly in notepad? And a column after the usernames Twitter, have a column with a sentence? In which, all these sentences, are the same for all other Twitter usernames?
If, for the case, I have misunderstood, please do not hesitate to contact me.
I have a wide experience in Excel and CSV. I believe I can help you as you need.
I'm waiting your contact.
Thank you!