"what is the requested time that it shows on the application to show the employment window?"
I have no idea what that means.
To extend your TN by mail, and be in TN pending status, you need to submit the I-129 on or before that date, and it must then be accompanied by a letter from your sponsor asking for a legitimate time period. If your firm is closing, and they know it, they should not submit a request for past that date. if it is for only 4 weeks, they have to put 4 weeks. The I-129 should request the period from Jan17 to Feb 15. If they did not knowingly intend to close, you would put the usual 3 year.
But remember, you also actually need to be working for the sponsor for your TN to be valid, regardless of the expiry date, so, it looks like you will be heading out of the country very soon. How is the job search going?