Your Help Needed! An Urgent Audio Question

As much as I love movies and showing them at the library, I know very little about audio, but I hope someone reading this can be of assistance.

A couple of weeks ago, the sound system we use for our Great Movies series at the library died. We use a Blu-ray player and connect it to a digital projector (above) with an HDMI cable. (Not connected in this picture)

For the audio component, we attach red and white audio cables from the Blu-ray player (audio out) to a sound system (pictured below). This sound system/amp was originally used for as PA system, but was given to us by library headquarters when they received a newer system. They knew we show a lot of movies and that it would come in handy. It has until now. The audio has completely stopped working.

Julia and I have tested everything, tried various replacement cables, etc. and are 99.9% sure it’s the PA system that’s busted. For one thing, it’s old. For another, it was transported from branch to branch for years before we ever got it. I’m not sure how old it is… The speakers themselves seem to be okay – we can hear them hissing when we turn the volume all the way up, but that’s all we can hear.

We want to replace the speaker system, but really don’t know what we want. We need something that can fill a room that seats over 150 people. I’ve looked at some home theater speaker systems online, but my concern is that they are too small. We also need something that is easy to set up and take down. And our budget is under $500. (I know that’s not very much, but that’s what we’re dealing with.)

Again, I know almost nothing about this stuff, so if anyone has any suggestions, they would be greatly appreciated. We will be able to borrow the new sound system for our next Great Movies event on August 3, but we also have movies scheduled at the library for August 24 and two events in early September, so time is tight. Thanks in advance for any help or advice!