I'm still pretty new to this so I may be wrong, I don't believe you can add zones but you could change the template page settings to set it up with more zones. However, my experiences with changing the Template Page settings is that the new template cleared the page and I have to start adding webpart all over again.

To change the template page settings:
Admin > Portal > Manage Pages > Pages List (click on the page to modify) > Click on the Edit Page button

The Template Page settings is as shown below:

Most pages are set with a "33%, 66%" template (leftzone and rightzone). A 100% template only has one zone because there is no split. The percentage shows the split sizing. Hope this helps.

That was it! Thanks!