In your case, it isn't just a to-be-read, but remember-to-get. Clearly pre-order isn't an option for you or necessarily even desirable. I thought about that considering the demise of Fictionwise. If you set up a Calibre library with the last volume of the series that you read and periodically select it and then click on GET BOOKS. Presumably, you have selected retailers where you can buy your items. I found more things come up when you click on a book with the author and then GET BOOKS than using the Get Books search button alone.
BTW, this works even if your volume has a DRM that you can't remove. You can load it in Calibre, you just can't read it.