Buy a hardware kit from the dealer for either Sirius or XM which includes an up front fee to that sat company (partially credited back with 3 free months), get the kit installed or see threads here with detailed instructions, pay the monthly fee after 3 months. There is a small box that connects to the head unit, and an antenna. Or you can go aftermarket, but since you have the sat capable unit, my first thought is to stay OEM. That's more than I know...
just remember it depends on how cheap you want to go, I paid $29 for my Sirius Radio kit. Granted I installed it myself and I don't have the prettiest radio of theirs. I installed mine just above the power button and I was able to tuck the wires in between the front part of the dash for a fairly clean install. One reason I went cheap with it is I am anxious to see what happens in their merger attempt with XM will upgrade my radio after they have their combined a la carte service.
The hot ticket for fully integrated, MFD controlled, 16 Character, Sirius satellite radio is the new Directed Electronics TOY-SC1 emulator and SC-C1 tuner. The two will cost you anywhere from $90-$150 total.(if you shop around.) And Does the same thing as the dealer's $800.00 system
I have a similar question (sort of), so I thought I'd put it in this thread to avoid making a new one. For those who installed either an XM or Sirius aftermarket kit, could you please describe or post pictures of how you have it set up? I'd like to get the satellite radio integrated with the MFD, but my Prius doesn't have the required package and I think it costs $300 to get an XM radio unit from some place like Coastaletech. I don't think I could justify spending that much money when I could buy an external unit for $100 or so and deal with the added clutter. But back to my original question...If anyone has pictures of where they've mounted their satellite radio units, please post them as I'm interested in buying one myself. Thanks.