I was there today, borrowed Lee Frost's Photography Guide to Filters AGAIN. NLB really has a lot of good books. You paid your taxes and some may have landed in NLB. Why not start looking through the local libraries?
Try the National Library branches and you will be surprised by their range of photography books. The "regional" libraries have good selections of most subjects of interest. Plenty of CS3 books the last time I saw.
I used to buy my books, but now borrow from the library as a first "filter" and buy only those I want to keep as a personal copy.
Lightroom can do some things faster, but LR can only do about 10-20% of what photoshop can do. Lightroom is targeted for photographers wanting to do some PP to their pictures. With photoshop, the sky's your limit. 2 very different products.
CS3 is already 2 generations behind the current version. If you find CS3 laggy and slow, your computer must be very very very old. And if that is the case, it will be laggy with lightroom as well.