Share 'Heeelp!! Item analysis'

My knowledge of Psychometrics is rusty. But I have to do it again...... someone help me please! I have outlined my problem in the blog below. Basically its an item analsysis problem. Core question being...when can I say my test is stable?     http://www.methodspace.com/profiles/blogs/what-i-am-working-on-psychometry-and-resilience