The date drop-down is controlled by the recurring settings within the page builder.  The days just need to be added and the page saved again.  Click on the DonateQ tab and select Giving Pages from the left-side menu.  Click on the pencil icon next to the Giving Page you want to edit.  Click the blue “Edit” link next to Recurring Donations in the Page Content section.  Under Display select Option 4 and click the calendar shown and select the dates you want included.  (Remember these are days, not specific dates, so you can offer gift scheduling for the 5th and 15th of the month for instance).  Click [Apply] once you are done, and then [Save] your page.