Awww congrats David!!! You're gonna have a baby!!

You will find that every time you go near her nest, she's going to fly away - this is primarily to distract you. The Moms will never stay near the egg(s), you might think it would to protect it, but what it's hoping you do is follow IT and not stay near the nest.
As for food...I have several doves that hang out at the bottom of my bird feeders, they seem to like the smaller seeds, whatever falls to the ground from the higher feeders, they eat the sunflower seeds as well. They LOVE to eat bugs...I'm not so sure you want to catch them for her!!!
Put a shallow bird bath or large bowl nearby so she won't have to work so hard to get water to the little one once it's hatched and for her to bath in. I'd also put some pieces of something fluffy nearby...she'll find it and add it to her nest - if you have any pets, pethair would be perfect...or pieces of string, yarn or the like (cut them up for her). They like to take dirt/sand baths too...so if you REALLY want to go all out...make a little place for her to do that so she won't travel off too far.
Doves lay eggs a few times during the season, so if you provide her with a nice safe spot, you just might be "growing" doves!!!
Lucky you!!!

Gotta love listening to them!
(oh...and the male usually sticks around to help out too, so if the "atmosphere" is right, you could have them around for a while!!!)