FYI: I just used Firebug to log the POST data while searching Advanced Search, and finally derived the following search to bookmark:
http://yourlibrary.com/BANGSearch.dl...ollDate=%3E*30
Change "yourlibrary.com" to the main website of a specific OverDrive library, and it should work.
Searches for everything in the last 30 days (that is the "30" at the end, you can probably change it to whatever), finds all titles even the checked-out ones, sorts by date added, and filters to only ebook formats and the English language.
I bookmarked it and since Firefox allows keywords, I type "${library}-new" to search for new books. (Modification of my previous method using curated collections.)