This topic has a good run-down on restaurants near McCormick Place: www.chowhound.com/topics/368426 As you can see from that topic, there aren't a whole lot of good places in the immediate vicinity. Cuatro (Latin fusion food - www.cuatro-chicago.com ) is the most notable exception, a few blocks away. There are good Chinese restaurants in Chinatown, about 3/4 mile away, and then there are more good places in the South Loop, starting in the 1300-1400 blocks of Wabash and Michigan which are a mile away or more. Just beyond walking distance of McCormick Place, you have TONS of great choices a short ride away by el (subway) or cab, including everything in the Loop, River North, Michigan Avenue, and West Loop areas.
You should also be aware that many restaurants are closed on Sundays, and many are closed on Mondays, but many others are open either of these nights. For a discussion of some of the best restaurants open Sundays, see www.chowhound.com/topics/378848 For a discussion of some of the best restaurants open Mondays, see www.chowhound.com/topics/455953 (Cuatro is open seven days a week.)
Once you review those discussions, you'll have a better idea of what's available, geographically as well as on those particular days of the week. If you have more questions, feel free to ask.
We just went through this last weekend with a nephew who was a) attending something at McCormick and b) staying with us Near North so here is a bulletin from the front: don't count on the Red Line subway weekends nowadays as they are shutting down certain downtown stations for construction. Take a taxi. Anyway I am convinced that the location of McCormick was chosen by the city's taxi drivers as it's pretty inaccessible otherwise. But as another poster has indicated, you will be a short ride from many good things.