Unless you need to know your number before leaving, just get one there. You can buy them in the airport in Moscow (SVO2 or SVO1) for as little as 300r...maybe less.
I've not used this company you mention nor do I know anyone who has. All Russian mobile providers now (as of July 1) have free incoming calls. SMSes vary from provider to provider. One plan I have allows the first 40 free each month. PM me if you want/need more details...