Yikes! I Sent My Tax Return to the Wrong Address

I used TurboTax to prepare and file my tax return using the 1040PC form. The printed instruction told me to put the return and Form W-2 in one envelope; the voucher and check in another envelope. The only address supplied was the Austin, Texas center.

I did exactly as instructed, then two days after the deadline I found out through someone else's IRS publication that returns without taxes due should go to Austin, while those with tax payments should go to Missouri! What should I do?

-- Liem Nguyen ...