Complete newb question

Ok, needing to setup audio to replace what sounds like blown speakers from a projector.  So the setup is this: From a pc/laptop, HDMI to wall, which then goes to the projector.  It's a Panasonic PT-VW530, it has an audio out Jack, but I it looks like it only does 0 V [rms] to 2.0 V [rms] variable, output impedance 2.2 kΩ and less, which doesn't seem like a lot to feed 2-4 speakers.  I am needing to cover a room that's approximately 30'x40' that usually accommodates a crowd of around 30 people that's talking low, I.E disinterested employees sitting in a meeting, the room itself is almost entirely large glass windows, white boards, and drywall (which I read is pretty much the horror story for audio).  I am not looking for studio quality, but having the sound from the meetings not sound like it's coming from somebody with Tourette's drowning would be great.  Now I -think- I would need something that would separate the audio signal from the HDMI and pipe that to the speakers, or if the audio jack from the projector would be sufficient I'd be more than happy to do  that.  Then I would also need speakers.  I can assemble, but I'm just second guessing myself on my calculations in regards to the specs of what I'd need.