Howdy neighbor!
You should be able to find them at any salon (excluding Supercuts and places like those -- they carry Redken but I can't find the "Extreme" line at those stores).
If you're looking into them, here's a bit more info:
"Extreme" won't make your hair baby-soft or do texture miracles (in fact it felt a bit rough to me at first), but it strengthens it and you begin seeing a lot less split appearance, and more healthy shine after awhile. "All Soft" just softens and makes it look nice (and fades dye a bit quicker than usual) but doesn't do much proactively for the damage. And "Glass," the laminate, will run you around $14 (eeek!) but you should only end up using several drops per day, so that bottle lasts forever.