The camera might be really easy - the car may already be pre-wir d for the camera. You can pull down the trunk lid liner and see if there is an extra gray connector near the center brake light. If it's there, you can buy a $200 kit to add the factory camera, then make a trip,to the dealership to turn it on.
The Nav upgrade is just as easy to do - but it can expensive upgrade. You can buy a new RB5 radio from a dealership that is willing to sell one, or you can look for a salvaged one. I've heard of an Ebay seller that will sell them a bit cheaper if you turn in your old radio as a core. The prices vary wildly, I've seen them as low as $125 and as high as $1600.
Once you get the RB5, it takes ten minutes to swap the radios, and it'll work right off the bat.