I'm not quite sure what your asking. Why can't you use File.Copy()?
You can select a file from a dialog using OpenFileDialog object, this will give you the file selected, having paths and file name then it's just a matter of copy...
You could use a function to copy like this:
public bool CopyFileTo(string filepath, string topath)
{
try
{
File.Copy(filepath, topath);
return true;
}
catch (IOException ioe)
{
return false;
}
}