If you don't have a selector for the editor, this means your instance was provisioned after the release of Forms 2, so the Forms 1 editor is unavailable.
Oh, and I missed your question Sara, sorry! You've probably already found this out by now, but for the sake of other users watching this thread I can confirm that you'd need to create new forms for the 2.0 functionality. There may be a way that Support could assist with migrating from 1.0 to 2.0, but I'm just speculating here.
Hi Michelle - when you create a new form in design studio or add in marketing activities as a local asset, you should see an option to select the Forms 2.0 editor now.
Just a note though, any existing forms prior to this past weekends release will still use the original Forms 1.0 editor.