I've just found that I have an aux setting does this mean if I get the correct cable I could connect a usb to my system?

Aux on the Stream is a 3.5mm audio jack in, and that's only on the Stream MP3.

you couldnt connect a usb to ANY aux. The aux socket is dumb and simply plays what is fed into it, a usb stick is simply a storage device so it wont send any audio signal to the headunit

Where do I plug in the 3.5mm audio lead?

If your car came with a stream MP3, the aux connection port will be in the jumbo box.

I just have the basic stream unit but It does have an aux. How do I find the input on the stereo?

There won't be one. If it's the non-mp3 stream there is an aux option on the menu, but there isn't a plug in the car.

 

You'll have to use an emulator that replaces the CD changer to add an aux in.

So I've found a plug in aux adaptor which I'm lead to believe will fit and work on my stream. Would it just plug in the rear of my radio is it that simple?

http://pages.ebay.com/link/?nav=item.view&id=281399897194&alt=web