Hi lemondrop,
It sounds like this particular listing has received a bid so the "Buy it Now" option has been removed.
It typically takes several hours for the information in your store window to change in the even of a bid, etc.
Our listing maintenance, which updates title, current price, high bidder, high bidder feedback, bid count, currency, and end time on your active listings page is done about every 6 hours.
Once your updated prices are reflected on your active listings page, they should be displayed in your store window the next time it refreshes, which it does about every 2 hours.
I hope this clears things up=)
-Mike