Your love interest may not have access to the latest model computer which can run your latest software. No, you needn't. When someone in Russia sends a letter abroad, the only Russian word the Russian post will need is the country of the destination. After that the letter will be passed to this country's post and they will proceed the delivery. There is no need to confuse mailmen in your country by transliterating or, worse, 'translating' your English address.
Translators deal with the most intimate sphere of human activity - pure mental activity.
Information leaks do happen in life, especially in business and politics, but I have never heard of a translator getting involved in a story. My letters don't reach the addressee, or it takes them months to arrive. If you want to write back in Russian, please do. Send your letters to St. The agency recommends it.