It is possible that some ancestors passed thru Ellis Island and some thru other ports like Boston, Philadelphia, Baltimore. You will need to locate a name of a town for your ancestors in order to proceed with the research but at least you know for sure it is Romania.
The spelling Moscovitch seems americanized as to sound correctly but not spelled.The more original spelling, it depends on an alphabet of each country coul be Moskovic', Moszkovics, Moskovitz etc.
The LDS-Mormons have filmed the church records of several European countries but I am not sure if they have done Romania.You can check out their website for films when you locate a village they came from.
There were 93 MOSCOVITZs that passed thru Ellis Island and several of them are from Jassy. A good website for locating a town when spelling is in question or from the old regime is: http://www.jewishgen.org/ShtetlSeeker/loctown.htmhttp://www.jewishgen.org/ShtetlSeeker/loctown.htm
If anyone of your ancestors were naturalized citizen or had social security numbers than you can request those forms which they should provide some usefull information for your research.