02 540i - Radio and nav problem

[Bimmerrules]

My radio was working fine and not sure why the stations won't tune in. I can find the stations and all it comes out it's that buzzing sound. I took to a stereo place and the guy thinks the tuner is out. Bad tuner? How do I fix this problem? Dealer wants me to change the whole radio...are you serious?!?!
On the other hand my nav sistem is not working properly. I locate my car and get the directions in but once I start driving the nav moves backwards... if I'm going north the nav moves south and vice-versa. Any idea what it could be?
Thanks in advance!!!

[Bimmerrules]

I guess that's a tough subject!! Anyways, it was worth a try!! Thanks!