They definitely need a waterproofing treatment. Shortly after I bought mine I returned to the car during a storm to find the inside completely drenched. The rain was coming straight through the fabric and dripping everywhere.
There are two big names for cleaning and waterproofing convertible tops; Raggtopp and 303. Different people prefer one brand over the other, but there's no definitive answer as to which is better. It's a matter of personal preference. I've never seen either at a local parts store like Autozone or Advance. You have to order it online. Just do a Google search. They are easy to find online.
Not sure you need a treatment. My car is six years old and I get the roof drenched regular a few times a year in a Texas size down poor. The fabric is always soaked but nothing gets through.
I would recommend to read the reviews on Amazon on the products listed in the posts above. There is quite a diversity on opinions.