There are most likely communications professionals on your campus that have local and national connections as well as experience writing press releases and marketing new campus services. It is a good idea to work with the library communications professionals and the communication professionals from the author’s college or home department to develop a promotion strategy and find appropriate news outlets.
The bookstore can be a great partner in promoting a newly published OER on your campus. Many campus bookstores have the ability to print on demand or can help you source an inexpensive printer. Bookstores also often work with faculty who are selecting new textbooks and resources for a class and may be willing to partner with you to set up a local event. For students, the bookstore provides a single information portal for finding all of their textbooks and class resources, even if those resources are freely available online.
Like libraries, instructional designers are becoming more involved in creating, disseminating, and advocating for OER, especially for online classes. It is very likely that the instructional designers on your campus are connected to communities that are working with OER and would be interested in helping promote newly published OER both locally and more broadly.