I'd be surprised if breakfast isn't provided by your Hotel and included in the room cost. On my last visit to Paris, I stayed at the Hotel Duquesne Eiffel and they provided a GREAT breakfast!
For lunch and dinner, there are lots of choices in that area. I usually just get a Baguette/Sandwich for lunch, and have more of a "treat" at dinner. Which restaurants to use will depend on whether you want a "gourmet" dining experience or something more "normal".
Some of the establishments I've enjoyed on past visits:
- Cafe du Marche: (have a look at the photo at www.ricksteves.com/graffiti/helpline/index.cfm/rurl/topic/40706/how-to-get-from-the-gare-du-nord-to-the-hotel-in-paris.html)
- Cafe Roussillon (not sure of spelling?): Menu is on a large blackboard, which is a bit unusual. I found both the food and the service to be good. It seemed like a very popular and busy place!
- La Terrasse: on the corner near the Ecole Militaire Metro stop. Food was great, seemed a bit more on the "gourmet" side.
- Cafe Central: dined there on my last visit and enjoyed the meal.
One that I can't recommend is Le Bosquet, which I believe is the one Rick used in his Paris TV show. I found the food adequate, but the service absolutely terrible. I will NEVER dine there again!!!
Happy travels and have fun in Paris!