Well, not really useful, since it doesn't support brackets.
Draft send by Rajganesh on the other hand doesn't support decimals. (of course, I can force it)
Don't have time right now to provide mine solution, but for this script to be useful it should works as follows:
select dbo.EvalSQLStatement('(5 * 3 + 1) / 3')
-- result should be 5.333333