Yes, you will have to pay a cancellation fee + the full new application fee. You CAN postpone the exam (by sending a new application) but it will be expensive.
I really recommend just paying the cancellation fee and sending in a new application.
...But If you really do not want to spend the money on the new application (plus the cancellation fee), and if you really have to take it in one week then this is what I would do:
-Pick one (1) slim comprehensive reveiw book that you used for your studies before...You mentioned FA and Secrets. Pick one that you are most comfortable with.
-Divide the day so that you spend half of the day doing UW questions (random, timed), and the other half of the day reviewing the review book of your choice.
If you decide to take it in one week, You have to booster you confidence level (very important).
Having said that, I still recommend just paying the extra money, and postpone your exam date.
Other people here might have better ideas.
Good Luck.