Talk about a sledgehammer to crack a nut. A hundred quid to send audio to the other side of the room using proprietary software? You’re all having a giraffe.
Bluetooth adapter for the laptop, I posted a link earlier but lets go for a posh one, ten quid. There are cheaper ones, you just need one which supports A2DP.
Bluetooth receiver (first one I fell over on Amazon), tenner:
Bosh. Quarter of the price of an Airport and no need for fruit-based software.
You need a decent quality DAC to obtain decent sound quality from Bluetooth, which will be expensive. The Airport Express is also a good quality DAC.