If you need the visa to enter Russia, please start to think about your travel not later than a month before the event.
The first step should be to get the touristic voucher (visa support) which you can order yourself and pay online, for example, at ivisaonline.com.
Normally, it costs 20–25 euro, however, if you book four star accommodation in Moscow, the visa supporting documents will be provided by the hotel for free. With the voucher, you can apply for the visa directly in the Russian Consulate in your country (in this case, you'll have to visit the Consulate in person, but it will be much cheaper), or can use the touristic agency service.
Please note that your passport should be valid at least six months after your planned stay in Russia.
For any help, feel free to contact us by e-mail, we'll be happy to answer your questions.