If I replaced my tires every time I got a nick like yours I'd go bankrupt.
If the tube is not bulging out of the hole, you're fine. Even if minor bulging occurs, booting from the inside will solve that.
To answer your other question: Conti makes a very puncture-resisitant tire called the Gatorskin which I started using on my training rides about 5 months ago. I've gone from flatting about once a month (600 miles a month or so) to zero flats in the last 5 months.
Bob