Не претендую на истину, но я бы так написала.Последний параграф Котенка.Dear Имя,My name is Anna and I am responsible for help in organizing an art exhibition in Moscow in May. Primarily, we have to discuss with Marina and approve which of your works will be presented on the exhibition. For the beginning, we can choose the images from your on-line gallery.My colleagues will support you regarding to your visit. Please find Russian consulate in your country to apply for Russian visa. Could you please send us a copy of your passport (the main passport page)? We need it to arrange a Visit Invitation and for a reservation (ticket reservation?).Looking forward to hearing from you soon.Yours sincerely –пишется, если в обращении указываете имя человекаYours faithfully – если имя адресата неизвестно