ummm post a pic of a section of it im a sprayer theres loads of products and helpful tips some as easy as heat the paint up with a hot air gun etc...

mate of mine had sunfade on his car all the time id buff it then buff again 2 weeks later,got talking to a geezer at the local meet and he was on about sun fade and his permanant cure was cheap white vinegar mixed in with g4 compound,thought the guy was crackers but thought give it a whirl and it worked.... not saying try this on yours its just i have a book of tricks so post a pic and ill see what is out there,,

however stay away from g products theres to much amonia in there products you might as well park your car under a tree and let the birds s hit all over it ....