In my VSE I only have a audio strip, no video strip and I want to slow down the speed of the audio, because I'm making an animation and want to get the lip-sync correct. Is there anyway to do this without the changing the FPS or anything like that?
The only way to do this in Blender is to change the Audio Strip's pitch value. Its in the Strip's properties panel in the VSE (N key). But it won't change the length of the strip nor will it change the waveform for you to see where the sound has stretched to. I would suggest doing an Audio Mixdown after the pitch change and re-importing it.
But honestly the sound will change to much, why not use Audacity free Audio editing software, it is open and there are portable versions available. It will do speed changes much better than Blender.