I think most of my suggestions have been covered already on here. One thing that was really good to get my daughter psyched up for the IVIG...there is a youtube video by a little girl named Sera, three months post-ivig where she talks about it making her better. I had my daughter watch this (though I stopped it before the end where the screen lists a lot of symptoms, some of which my DD doesn't have -- I didn't want her to start fixating on other things that might crop up other than what she already had!). It really gave her confidence in the medicine and gave her the courage to overcome fears about the process and aftermath. Good luck!
Didn't edit this post, it looked like my comment was going to be just added to your...new to this and figuring it out.
But, thanks for the you tube video I will check it out.