Chances are that if anyone "invades" us, they will be using 7.62 x 39 anyway, so I wouldn't worry much about "getting aid" from Russia. Most of our current enemies, hell most of the rest of the world, uses 7.62 x 39.
As for me, I suppose I'd grab my AR, a couple of Glocks (.40), and a 12 guage. I am larger than most people, so I do not move quick, but can pack like a mule...