Speakers/receiver for classical music and opera on a budget

I apologize in advance.  You are all audiophiles and I'm only a beginner - and a poor one at that.  But I am desperate for some help.  Finding the right speakers and receiver, on a budget, for CLASSICAL music and OPERA is very, very hard.  I have a 13'x13' family room and $600.  I'd like to plug my computer, dvd player, tv, cd player and speakers into the receiver.  Please don't hate me for getting on here to ask for help.  You men/women are music gods and I need some miracle.  I'm obviously poor and don't know a thing. Right now I have Infinity Reference 2000-3 speakers and a Yamaha RX-395 receiver - if I plug my MacBook Air into that it really sounds bad.  I've been listening/watching opera via streaming/dvd on my computer with headphones.  A 3-hour opera with headphones is long.  Anyone care to help?