Welcome to FlyerTalk,
dtwmsy!
You can upgrade the T fare with miles if there is mileage upgrade inventory, which is not guaranteed. I don't know how many miles will be required, I'm sure somebody will know and post it shortly. However, I would suspect it will be a poor value.
You may want to consider seeing if you have a FCM (First Class Monetization) pay-to-upgrade offer. You can do this by looking at the itinerary or seat-map on Delta.com.
Finally, you may want to hold off on calling for a day or two. I just tried to call as a PM and was told an hour wait, apparently there is severe weather on the East Coast.