Don't bring in the prayer books unless they're for your own use.
Or, to put it a better way, be careful that it's not a prideful thing. I remember self-consciously bringing books and putting them out on my desk, or wearing my cross everywhere, or listening to my music too loudly, in the hopes that somebody would ask me. It feels like I'm trying to trap someone, so I made sure that everything I did was genuine and coming forth from my own personality, desires, etc. People still ended up asking and I didn't have to carefully arrange myself on the library couch with a CS Lewis book held up to my face.
You are already speaking about Orthodoxy with them, so that's good. I think that disbelief is also a very strange reaction. So strange that saying, "I invite whoever doesn't believe me to attend DL with me on Sunday," could actually be par for the course. Either they all laugh and you can just shrug it off and go your merry way, or some might come out of curiosity. You never know.