Hello Im Sourish, I'm a Linux, asterisk, network expert. I am a raspberry pi enthusiast. I have setup this at my home. I can help you to setup raspberry pi as a upnp streaming client and you can send audio from your Windows PC over wifi. I have the image for raspberry pi 2. Hence i can send you the link to download it and install it on your raspi. You will have a out of the box solution. Please let me know and we can talk further on it.
You can try it with me and if you are satisfied then you can pay me. Looking forward to hear from you soon and hope to be a part of this project.
Thanks
Sourish