New monitor questions

[.Maleficus.]

I'm thinking of getting a new monitor. Specifically, this one. I've decided on that because it has DVI and HDMI, is 22" and not too expensive. Here's what I want to do.

Xbox 360 on HDMI
Computer on DVI
(If possible) Share z-5300e's with both
Use my Turtle Beach X1 headset

The problems - The monitor doesn't have built-in speakers and I'm not sure how I'd hook up my z-5300e's anyways. Is there some sort of box that I can take the HDMI cable into, and have it output to another HDMI for video and then the speakers for audio?

This brings me to problem #2, if that is possible, can I share the speakers that way as well? Or would I have to unplug/replug every time I switch?

And for problem #3: The Turtle Beach X1 is meant to be a headset for everything, ie, game audio and voice chat. Because if this, it connects inline with the red and white RCA cables behind my TV. Well, the monitor is HDMI. You can see the problem . I'd need some way to output to those too. Does such a magical box exist? Would it mean like, buying a DVD (or Blu-ray as the case would be) player to do this? Before I pick up the monitor, which I was hoping to do after work today, do you think I'm in over my head? School's just about to start, my hours will be cut back to ~20 a week and I don't want to spend $500 just to play my 360 in HD.


Edit: I just looked at a couple of Blu-ray players and it doesn't look like any have HDMI in- so this doesn't look like it'll be easy.