A few ideas for locating the IAS (three parts: manual, evaluation forms, summary and planning forms) -
1) Is your child a DYS?
2) Does your local school have this on hand?
3) Does your child's tester/evaluator/psychologist have this resource available?
4) If you choose to purchase the IAS online (new or used), be aware that the 3rd edition is current, as you may find some 2nd edition copies.