While it is possible to call them immediately, it is better to send a letter and photograph so that the women will know who you are. It is important to remember, no matter how well a woman speaks English, it is best to speak more slowly than usual and not use slang - it isn't being tought in schools. Also, Russians learn English spoken with an English rather than American accent.
Most women live with family or roommates.
It is possible that your call may be answered by someone who does not speak English. If she is home and you speak her name clearly, someone will bring her to the phone. Be aware of the time difference between Russia and the U.S., and plan your call accordingly. Contact your long-distance carrier for best rates and times to call. There can also be a wide variation in the rates different long distance carriers charge and you may wish to shop the rates and use the access number for the carrier with the best rates - especially if you intend to make several calls.