Friend - Sorry I am coming in to this late. I am glad you opted to get the w/c. It will make the orientation more enjoyable for you as well as DD. (Well, as much as an orientation can be enjoyable. LOL). And, you are getting a free ride and your seating is taken care of! How cool is that?
As others mentioned, I would call the neuro and let him know the oral steroids aren't doing anything for you. I can't remember what issues you were having with this flare. I do know, from my own experiences, that spinal flares take what seems like forever to go away but generally up to 8 weeks for me. Is that possibly what is happening to you?
As for tomorrow, try to put as much out of your mind as possible and focus on DD. Try to make the day about her as much as you can. I know this is very difficult to do and as moms with MS we have to force it but the our kids appreciate it so much when we do that for them.
Pack snacks, ice packs, and lots of water and have a great time. Let us know how it all turns out.