Hey frown all you want here!!! We got your (cyber) back!!
I think the outfit sounds good, you could wear the jacket either way but conservative is good for a senior living place.
In term of confidence I would start practicing your interview skills now. Do you have a someone who will come role play with you or maybe do it over the phone. Your confidence will build once you practice. Also, as bad as it sounds, the more practice you get the better it will be so even if you don't get the very first job you apply for look at it as a learning experience.
Also it sounds stupid but have you shook hands with anyone in a while? I never do now that I am not working. If you haven't, have someone check your handshake. Should be firm but not bone breaking. Make sure you make eye contact. At a job fair these people could see a ton of people. You want to make a good first impression.
I googled "top interview questions" and found these sites. Write down you answers and practice them so they sound natural but you are prepared so no umms, awkward pauses. etc. Then give the questions to a friends and have them rephrase them so you can answer them all smoothly and easily. Even if none of these questions come up the process of thinking about your answers and feeling comfortable will do loads to improve your confidence!
http://www.collegegrad.com/jobsearch/Mastering-the-Interview/Ten-Tough-Interview-Questions-and-Ten-Great-Answers/
http://www.bspcn.com/2007/08/24/10-killer-job-interview-questions-and-answers/
http://www.wisebread.com/how-to-answer-23-of-the-most-common-interview-questions
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