How to get data from apps when upgrading to iOS 5 on an iPad 2 I updated my iPad 2 to iOS 5 using my Windows PC. 

I backed up my apps, calendar, mail, photos, etc. using iTunes before the iOS 5 update. However, although I got my apps, I am missing all the data in them! For instance: for iAnnotate PDF I am missing all my annotated files, in Note Taker HD I am missing all my notes, and most importantly in bizXpensTrkr I am missing all my business receipts and data!

Can someone please advise in layman's terms? I am new to Apple and used a PC to update.
Do you still have your backup? 

Connect your iPad, right click it in iTunes' sidebar and select restore from backup (Sometimes it helps to restore from backup twice).