Hi Yvonne,
Thanks for your post. At this time, there is no built-in way to add your additional fields to the Filter Bar. However, we are planning on adding that feature in a future release. If you’d like to stay updated on our progress, I recommend that you add your votes and subscribe to our UserVoice thread for the feature.
If you are interested, you might also be able to do some custom work to get additional fields working with Filter Bar. You might check out this thread and this thread for some tips on how to get started. Please note however that aside from pointing you in the right direction, we are not able to provides assistance with this kind of complex customization.
Good luck, and thanks for using The Events Calendar!
Best,
Leah