You won't find it in traditional drug stores. Try The Vitamin Shoppe and maybe GNC or a "health food store". If they don't carry it they might be able to order for you.
Most folks tend to take much larger doses than you'll get at most drugstores, for those you'll have to look to specialty health stores or online. I'm taking 5mg K2 (MK4) from Carlson Labs now, pretty cheap on Amazon.
I found this online and order it online as well http://tinyurl.com/q8fjc93 It is made in USA; head office is in California. That's why delivery and handling is free in USA. Delivery took about 3 to 7 days. It has Omega 3+ as well as CoQ10 and Vitamin K2 and it is Extended release(long-term effect).
I take Calcium with Vitamin K2 cuz Vitamin K2 helps direct calcium to the bones and teeth(where it belongs), keeping the calcium from attaching itself to the arteries. I also notice I had smoother skin after weeks of taking it. Natural sources are Natto, egg yolk, butter...problem is I don't like the cholesterol in egg yolk and butter and I don't like the taste of Natto.
I really like this combined Vitamin D & K1 & K2 supplement: http://www.naturalhealthyconcepts.com/vitamin-d-supreme-DFH60-p-designs-for-health.html?currenttab=2
You can buy Doctors Best Vitamin K2 in stores. Check out their page and "where to buy":
It is a good product, with the natural vitamin k2 (MenaQ7)
Both pomegranate and cashew nuts have high amounts of vitamin K. Don't know if it is K2 though.... Sweet chestnuts also contain, some, as do avocados and kiwi fruit.
If you eat dairy, you could try a natural high source of K2 http://www.thehealthyhomeeconomist.com/gouda-the-nutrient-dense-cheese-of-choice/