You could do a simple string split and order by the split piece (what about names like "Bobbie Jo Robinson" vs. "Brad Grafelman" ? - solution gets a little lengthy), but this means that the SQL server is going to have to split the data in each row every time the query is ran.
A lot of CPU/RAM could be saved by doing as Bjom suggested; invest a little work now to fix the schema to save yourself the trouble in the long run.