You don't really need one if it's for your own use - in VSD tracker I had the same problem, I was looking into creating the .wav from the raw data, but that's a lot of work. Hubdule sent me some nice code that uses an internal .dll to record a .wav from any source, you have to set mixed output in the windows volume controls*.
If it's for a one off, you could just record the mixed output in a sampler.
* Note, it might be known as Stereo Mix, you'd select it as a recording source in the volume controls, I find about 30% volume is a good limit, otherwise it'll sound like crud.
Van-B

It's c**p being the only coder in the village.