Hello,
I have prepared a build for YafaRay v0.1.5 for Blender 2.73 in Windows 7 64 bits and Windows 8.1 64 bits. I hope it works for all or most people.
For more information, download link and a screenshot:
http://www.yafaray.org/node/612#comment-806If it works and you are happy with it and you still want to give your 100$, then please donate them to the YafaRay project using the Donate menu in this website!

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I hope it helps. Let me know if you have any issues.
Best Regards. David Bluecame.