First of all, you should narrow down the type of restaurant you want. "Appropriate" and "decent" are extremely broad terms. I'd start contacting restaurants directly and ask about your options given your price limit and the fact that you want it to include drinks and gratuities (and dessert?). I think you want a fixed menu. A couple of hours may not be that long when it comes to a group, especially if people are going to each decide there what to eat, and start to talking, etc.
The somewhat upscale Fish Market restaurant, with two floors having different menus, is good and has a nice location, almost next to the USS Midway. Here's a sample lunch menu:
http://www.thefishmarket.com/menus/d...s/sd_lunch.pdf. It's not a long walk from the convention center but you may want someplace closer. Many restaurants add a fixed gratuity of 20% or so for groups over a certain size. Your group isn't very large, but some restaurants might be willing to provide a fixed price meal, with a limited choice of menu otions, so you have a better idea in advance what it will cost, no matter what individuals choose (e.g., someone chooses the lobster or drinks booze and you could have problems). I would think liquor would not be included in what you're expected to arrange; that they'd doon your own. If it is included, then the variables skyrocket.
There are a few restaurants virtually across the street from the convention center, next to the Omni Hotel. If you contact the convention organizers and/or convention center administration, I bet they'd have a list. The convention center may even be able to arrange a small luncheon on site. You're certainly not the first person to have to organize a group meal there.