Any advice on approaching them on this?
Just be direct. You're certainly not the first financial aid family that's found themselves in this situation, so there's no need to be embarrassed. There either is or isn't a financial aid fund to help cover things like this. So, they may cover the entire cost, they may cover part of the cost, or they may not be able to help you out at all. Just ask - and the sooner, the better.
By the way, uniforms may also be something the school can help you out with.
All of this varies from school to school. So, for prospective parents, it's always a good thing to ask as many questions as possible. The reality, though, is that there will always be something you didn't think of!
P.S. About travel, I'd recommend, if possible, using an airline that will refund the difference if a ticket price drops after you buy it. I use JetBlue and almost always get a significant refund sometime between my way-in-advance purchase date and the eventual date of departure. The refund goes into my son's JetBlue account and helps offset the cost of the next