You'll have so much fun! We loved the wave pool. :)
The have pizza right near the game area that is standard home-delivery type pizza, a bit more expensive. They also have a recently renovated restaurant which has pretty good food but is very pricey.
Most rooms have a mini-fridge and microwave, so you can bring snacks like cheese sticks and yogurt and fruit and have them on hand. There is Target in Grapevine not too far away. :)
You could go to the Rainforest Cafe (quite the restaurant experience, with animatronic rainforest creatures everywhere) in the Grapevine mall, which also has the Grapevine Aquarium and Legoland if you are interested in some other activities.
There is also an awesome sandwich shop called Weinberger's Deli in downtown grapevine, which is worth the trip (IMO). Sooo good.