Hi, I just bought a BenQ MP512 short throw projector to use with my Wii. I'd now like to add a decent sound system. I don't have an amp or any other piece of music equipment. My budget is approximately $300. Can you recommend something? I assume I will need to buy an amp, not just self-powered speakers? And when I'm shopping for a system online, how do I know if the system has pro logic 2? thank you!