What you are playing sounds like the guts of a *.bun file. You might get lucky and be able to rename it ".bun" and see if SONAR can unpack it.
If not, you can split the audio out (the wavs are daisy-chained end-to-end inside a bun file), but would then need to re-assemble it, and the MIDI data would not be available that way. Splitting it apart will leave you with a audio jigsaw puzzle of sorts, so how easy it would be to re-assemble would depend on how well you remember it.