^^ Chid: I suspect that your female connector is a special VW unit that you won't be able to find except at a car wreckers!
I'm not sure what size the pins are on your connector but they look like plain, ordinary, "spade terminals" (albeit, they look a bit longer). It might be possible to make-up an alternative connector as part of the wiring loom for the new audio bits using 4 x individual spade terminals of the type in the pic below (with heat-shrink tubing around the entire male-new female fitting if needed).
When I use these terminals, I remove the blue insulation and I solder the wire into the receptacle instead of crimping. I find this makes a better electrical connection (especially where the terminal needs to carry high-current). I then re-insulate the back of the terminal with two pieces of heat shrink tubing on top of each other.
Of course it would better to get the right female connector, but if this is not possible, "spade terminals" might be a good second solution