Dealer can't fix slide out and warranty running out! HELP

Personally, I wouldn't accept 1" out of alignment as normal. It wasn't misaligned by 1" when you bought it, right? You need to insist that they correct it. If they still won't fix it, have a 3rd party expert look at it (another dealer) and call the manufacturer to complain. Get your concerns documented so you can support your claims if you have to fight with them later.