Short answer: Google doesn't update things quickly.
What you can do to help rectify the problem sooner, provided you did everything right at your end, is visit Google Webmaster Tools and go to the section where you can fetch pages using Google and put in both URLs you mention to see if it can pick up each page correctly. One should report a redirect.
Then choose the gear icon at the top right and visit Site Settings. In it you can change the crawl rate of your website. Choose the option to specify your own crawl rate and move the slider all the way to the right.
You should see better results overtime if all goes well, and if your site is small enough, then the results should happen within a week.