I'm a little confused about what want to do. I'm not certain, but it sounds like you want to use your PC as the playback device, and have some way of connecting your PC to your stereo and controlling playback. Is that right?
I have a Squeezebox (SB, can't remember if it's original or v2) connected to my stereo with the Logitech Media Server (LMS) software installed on my PC. The SB is connected to my stereo via S/PDIF out (could also use analog-out) and uses wifi to connect to my PC / LMS and play back internet radio and my PC-based music collection. The SB also supports playing podcasts, but that's not a feature into which I've delved yet. I use my Android phone + the SB app to control it, which I find a much better user experience than the original remote.
Looks like the SB has been replaced by the SB Touch, which doesn't require a remote since it has a touch screen (though I'm sure you could still use a remote and/or Android phone app). Depending on your preferences and budget, you could try either a used SB, or the new Touch.
The Acer Iconia 7" sounds like an intriguing idea, but I would be wary of the quality of the (presumably analog) connection between the tablet and the stereo. (Likewise for your old phone.)