In your case, it's your status that expires on 7th March. I assume you mean that your DS-2019 expired on Feb 7, not your visa, because your visa doesn't matter once you are inside the US.
You are still considered in status for the 30 day grace period that ends on March 7. Afterwards, you will be out of status. Since your card is D/S, and your status expires on March 7, then you must file a non-fraudulent adjustment application before that date in order to remain in favorable circumstances. You will not accrue unlawful presence after March 7 even if you do not file for adjustment, but if you try to do anything with USCIS after March 7, they will notify you of your falling out-of-status and you will begin accruing unlawful presence on the day you receive that notification. So submit whatever you are planning to do before March 7. Again, it's not your visa but your DS-2019 that tells you when your status expires.