Hi there. This is a really great question. I have two questions for you. First, what is the number one goal you are trying to accomplish by attending this trade show? Is it brand awareness, collecting leads, conducting on-site sales, etc? Second, what metrics for success have you developed for this event?
Marketing budget allocation for trade shows should be goal-based in my opinion.
The first thing that comes to my mind is to use your products to market your products. You mentioned that your organization sells video, audio, etc. You could create a digital brochure and/or an electronic press kit that you can display on your screens (sorry, I don't know which products you have, specifically). You can also email these to leads, clients, etc.
Depending on your audience, you could potentially do something relaxing or entertaining. I use to work in the software industry, and people would flock to booths where they could play Guitar Hero, etc. There are also plenty of promotional items you could offer that are inexpensive for you, yet loved by attendees.
I'd love to help you brainstorm and come up with an awesome trade show marketing plan. Best of luck!