Yes, you will need to revise your listings through eBay. If you want to revise the category on one active listing, select the listing, hit revise, go down to edit pictures & details, and then pick the category, and submit. For bulk editing in eBay, go to:
My eBay>Selling>click the box next to the items you wish to change>click Edit near the bottom of the page>put a check in the box of the changes you wish to make (like categories)>check Edit Listings in Bulk>click Continue>Drop down the menu for the category and select Edit>a new drop down will appear to the right, select the right category>hit Continue>the next page will show a review page to make sure everything is OK. If everything is OK for all of you listings then hit submit and you're done. Hope that helps.
Doug