ask for visum to visit our relatives which we did not see for a long period of time and to visit grandfather's grave

A lot of our relatives have left ex-USSR in 1970s'. I was so young when they left my native city Odessa. My father died at 2011in Odessa. Two brothers of him live in USA that is why I really want to meet with them in real life. One of my cousins will have a child soon and it will be pleasure for me to see her.My grandfather has died in 2004 and at 17th of March 2014 my grandmother has died as well so I would like to visit their graves.