2003 GS430 keyless entry and navigation troubleshooting

Hey guys what's going on, I have a 2003 GS430 with navigation and having some issues. I used to have a Mercedes C43 AMG and was driving that rare monster while my GS was sitting in my garage. I guess all the time passed the battery died on me, so now my keyless entry does not work, I was told because the battery died so I have to reprogram it. Is it worth taking this to the dealer? I have instructions on how to program it, I just wanted to know what you guys think. And also my navigation is acting up a little bit. With the climate control the climate can not go any higher than 32 degrees farenheit when I want to heat the car, why is that from what you guys think? I haven't driven it yet with the warmer climate but I'm sure the A/C is okay, the heat probably works fine too but the tempurature part will not let me take it higher than 32 degrees. I hope someone can possibly help me out, I would greatly appreciate it. The GPS itself works fine.

if you can reprogram it yourself,i would do that..the dealers charge like 70 and up