http://pages.ebay.ca/help/sell/sellinglimits.html
When you list an item, you may see a message letting you know that you have met, or are close to, one of your monthly account limits. If you don't want to wait until the next month to continue listing, click the link in the message to request higher selling limits. You may also find this link in My eBay > All Selling in the Monthly selling limits section.
You can also phone ebay and ask to have your limit raised but I wouldn't do that more than once a month.