Before you do anything else rethink you speaker choice. Can you still return them? The speakers are the heart of your system and accounts for perhaps 90% of what you hear. Bose speakers are premium price for a low end product. Threre are far, far better choices out there IMO. My thinking is that 70% or so of your total audio budget (not including video) should be allocated to speakers. The only way to know what speaker is for you is to audition, audition, audition every speaker in your budget that you can find. There is no way to get around the audition part of building your audio system. Once you have choosen your speakers then you can think about the receiver, DVD/CD player etc that you will build around them.
Nick