It sucks, but don't blame the shop -- blame the continual change in parts spec driven by the manufacturers and market. Like Andy pointed out earlier in the thread, this would be like expecting your local car garage to have everything for your 10-15 year old car on the shelf*. They can't do that *and* stay in business.

Niagara Cycle has a couple of the 13-25 cassette in stock, as well as some 14-25 and 12-23. I'd just go ahead and buy a couple and call it a day.



* I use this year range because I expect that 9-speed bikes shipped with the tighter "racing" cassettes early in that generation, and more with the wider-range cassettes as they trickled down to lower product tiers.