I noticed that it lets you get a piece of gear above availability 12. what about programs? I have seen gear with ratings of 7 with 20 availability. I cannot get this with the restricted gear perk due to the Rating of 7?

Correct. It only raises the default Availability for one item; it doesn't uncap the rating: 6 limit. Although you might ask your GM to house rule otherwise.

If your GM cleaves to the rules, I wouldn't bother. You get one month or so out of that r7 program before it's no longer cutting edge, and drops down to r6.

Only if it's unregistered (a.k.a. hacked), or you don't spend some time to patch it yourself.

Or if you don't have a subscription to a hacker group that can do it for you (group contact/monthly additional charge).