I have a Point shapefile from arcGIS 10. I want to get it in r and also want to get it a specific predefined coordinate systen for my data. I can read the shapefile in R but summary in r Shows projectltion info like this `proj4string : [NA]' and if i want to transform the reference systen it Shows something like this:

Error in spTransform(xSP, CRSobj, ...) : 
 No transformation possible from NA reference System
What can I do to deal with this Problem. Thanks a lot:-)