No offence Miss Jane, but recommending that someone by a book in order to get advise is not helpful. Yes, it's has great reviews. I haven't read it. I've read parts of "New Rules of Lifting" but only the parts that are available free online. I would also recommend reading "Starting Strength" by Mark Rippetoe.
The basic message that I have for werhardt is to continue on your current program but start substituting free weight exercises as you learn them. The program you are using now is actually a very easy way to exercise since you are using small parts of your body at a time and you can limit the weight to what you can locally handle. At least you will continue to be active while you learn the exercises.
Using big compound movements is hard. Doing HIIT instead of steady cardio is hard.
They work because they are hard but no one else in your gym will be doing them except for you because they are too hard.
You have to decide if you're serious about getting strong and lean. You can continue as you are and you will see typical results. Few are happy with "typical" results but are unwilling to take the next step.
The exercises you need to learn are:
Squats - Back squats, front squats, overhead squats.
Beadlifts - Conventional, Romanian aka Stiff legged straight back, and Goodmornings
Presses - Bench Press, Military overhead press, Incline press, Dips
Pulls - Bent Row, Pull up, Chin up, Power Cleans
You can learn more about these here:
ExRx.net Exercise & Muscle Directory
You can put them together in a program by following one of the programs here:
ExRx.net :: View topic - A small collection of basic routines - update -01/30/08
The "Starting Strength" Program is on that list or you can link directly from here:
http://forum.bodybuilding.com/showthread.php?t=998224
HIIT is a very effective way to exercise but it is not for the faint of heart. If you are not able to maintain a challenging pace for 1/2 hour yet, continue to that goal first. You should be trying to achieve competance in at least 3 movements, for example, running, swimming, rowing, cycling, etc. Once you are comfortable, Start considering HIIT. You will be able to achieve a higher level of fitness with less overall work but it requires a level of intensity few beginners can tolerate.
High-intensity interval training - Wikipedia, the free encyclopedia
Stu