Interview help! I need help brushing up on IT skills!?

I have been made redundant and am applying for jobs as an admin assistant. I have experience but it was 7 years ago before I had my babies, and have been working as a cook in a nursery the last two years. I have already had one interview but have been called back to do some admin tests on excel, powerpoint, spreadsheets and other basic admin skills. My confidence is shaky as it has been 7 years since ive done any of these! Can anyone recommend any programmes I can do online cheaply or even free!