So you are looking to do a decent lighting and sound package for a cafetorium. Probably the best thing to do is talk to your local
theatre supplier. They should be able to consult on a project of that scale. You will need to know what your approximate budget is, or people will always try to push the most expensive gear on you.
As footer mentioned, you really don't want to take this project on without some kind of professional consultant. Yon need someone who can look at electrical requirements and the electrical constraints of your space. You need someone who can recommend appropriate gear and install or teach you to install it properly. Establishing a good relationship with your local dealer is a very good thing as they will be the first people that you go to when you have problems.