Thank you for posting.
It's absolutely possible to connect to a FileMaker Pro hosted database from FileMaker Go if you're connected via WiFi or 3G.
To do this, you would open your database in FileMaker Pro and turn on FileMaker Network Sharing through File -> Sharing -> FileMaker Network. After that, ensure the "Network access to file" option is set to All users on that same screen.
Once this is done, you should be able to access it from FileMaker Go without any further setup as long as you're on the same network as the computer hosting the database. If you're not on the same network, i.e., you're connecting through 3G or a different WiFi network, you'll need to setup something called port forwarding. For more information on port forwarding, you should check out the following knowledge base answer:
Please let me know if you'd like any clarification on the above.