Poor Keyfob range

I understand that this issue has been discussed quite extensively. So if anyone asked, I did do a search. Anyways, like the title says the range of my key fobs are pretty poor. I am still lucky to have kept both of my original keyfobs when I bought my truck in November 20, 2000. I remember the range being pretty decent back then. Now I literally have to be within 10-15 feet and with in a clear line of sight for my key fobs to actually engage lock/unlock/panic functions. Key fob Batteries are brand new. Car battery is brand new and recently tested.

From what I read here:

http://www.benzworld.org/forums/w163-m-class/1677893-remote-start-push-start-keyless-entry.html

It's my understanding the communication method for these key fobs is via FM modulation? Yes? In post #3 of the provided link shows the picture of keyfob antenna attached to the AAM? My question where does the wire lead to? Does that connect to the GPS/FM/TELEAID amplifier? If so, where is unit located? If related, would replacing that unit with a new or remanufactured one resolve the poor range? Or would acquiring the GPS antenna mast might work? Maybe not huh?

Thanks