If she is Russian her normal passport will suffice. She is a member of the CIS (Confederation of Independent States), the former Soviet states so no international passport is needed.
I'm curious as to why you're not traveling to Russia. It isn't that difficult to get a visa, registration is easy, and the HUGE advantage is that instead of starting the relationship out with a honeymoon/vacation, you get to go to her country and see her in her natural environment. I don't care where "else" is, anywhere but home is not her natural environment.