Von Totanes, in his blog, Filipino Librarian (I've dropped "the") has identified the guiding principles of marketing. I suggest you print a copy of this and share it with colleagues. Or, in your next departmental meeting discuss the issue of marketing the products you offer to your clients. Better yet, consider devising a marketing plan for two or three years that is anchored on departmental goals.
This way, you can prepare logistics for the marketing strategies you wish to do. Aside from the "money" issue, identify other resources to help you realize your marketing plan. It may be another library, a foundation, a publishing house, a book dealer/jobber, the local government, the alumni association or the school's parents association. Collaborating with them lightens the load and widens your connections. Networking is always good for the library for it to survive. Just make sure that objectives are clear and that the benefits will always go to the library's clients.
You may think that only the library coordinator is in the know of such decisions, plan or strategy. Again, I reiterate the importance of leadership both in the top level and in the ranks. The force must be strong on both poles or there will be an imbalance. Goals may not be realized and resources (including money) may go down the drain. When this happen, your clients are short changed.
Lastly, marketing is one way to improve an image problem. School librarians need a make over. We do. Let's admit it. Start with polishing your communication skills. Reflect on your role in the school community. Be prepared. Plan ahead. Plan long term. It will not be easy, but it can be done.