Thank you for your question. The rule is you had to live there two out of the last five years. Not two years while the owner of the apartment.
The US-Russia agreement is there to eliminate double taxation. Therefore, if you're not taxed in Russia, then you can still be taxed in the United States. You would pay capital gains tax which has a rate of 15% if your income is below $400,000 per year and 20% if your income is above that amount.
You need to have, for your own records only, the purchase price and sales information. You do not have to furnish this to the IRS unless they ask for further information in the event of an audit. You would need, at that time, to have an official translation. Therefore, it doesn't hurt to get this now so that you have it in the future.
Please let me know if you need any other additional information. Thanks again for using JustAnswer.com and have a happy, and safe, 2013.
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You should be aware that your question, as with most tax questions, can never really be answered completely...addressing all the permutations; that is because of the many assumptions that have to be made I have done my best to determine what I think you are asking and answering it in the most direct and understandable manner possible. If, however, after reviewing the questions, you have any uncertainties or further questions, please do not hesitate to ask.