When you say you are not learning enough at work to help you pass, you are not saying that you have taken them before, are you?
I'm sure you know most of the info. I'd recommend bying a NCLEX book (Saunders, Kaplan, etc) and doing the practice questions. Most of these books have the practice questions by content. After doing the questions you will have an idea about what areas you need to study. This way if you do poorly on Cardiac, you will study cardiac and not the entire book. I'd recommend doing 1500-3000 questions befor taking NCLEX.
This is what i did, and i can honestly say that when doing the questions i did not think i was doing so well. Sometimes i made between 65-100%.
Can you order a NCLEX book from amazon
I would really recommend Saunders. There is a NCLEX review book and a supplemental book that is ALL practice questions. Both books have CDroms with a ton of questions as well as the questions in the book.
I hope this was some help. If you have any other questions you can PM me or i'll check to see if you respond.
Good luck. CR