Cordelia has the first two books in the series, then Young Miles has the next two IIRC. Thats the ONE thing I hate about book stores (even Chapters does it), you go in and look at a book, it seems interesting and then you find out its part 45 of 68 and part 1 is nowhere to be seen. ARGH.
Luckily our local chapters seems to be ok at stocking titles and we have several good 2nd hand book shops.