Check out masterbell.com and find a plan that you like for price, minimum billing increments, etc.

Choose their "SMS Call" feature and set it up. You can then set up a call on your mobile phone in Russia (with the SIM you bought at the airport as suggested above) by sending a text message to a number they will provide you with the number you want to call in the States in the body of the message. In about 20 seconds your phone will ring and you'll hear the number ringing you are wanting to call.

The immediate charge to you is only an SMS charge (varies per plan) and money, amount depends on what plan you choose at masterbell.com, comes off of the prepaid card you purchased.

I use this all over Russia and it works remarkably well.

PM if you have questions...