Sending near real-time audio over a 250kbps wireless connection will require some form of compression or another, so you won’t be able to get “crystal clear” audio. Though there are good codecs out there that will give you pretty good sound quality.
Just a quick thought to ponder, it may work to stream a MP3 file over the wireless link from a computer, then on the Rx end you can interface it to an MP3 decoder IC (probably with a micro controller and some glue-logic in between)… That way you get the benefit of a good codec without having to mess around with decoding it yourself… If you try it, I’d be interested to see how it turns out.