My view is that if you are paying for it, they should be able to provide a suitable alternative meal. Can you contact the organisers in advance, to see what they could offer as an alternative? If they can't do that, you should not be paying money for food you can't eat, especially if you are on a tight budget, it does not seem fair.
Thank you. I didn't see much of anything on the restaurant's regular menu that was gluten/dairy free except for a salad, but it's worth asking. Otherwise, I would probably save my money. Thanks for the feedback!