Thank you for your post.
FileMaker Go does not have the ability to host files. That is, FileMaker Pro cannot access a FileMaker Go file as a guest. You would have to either email the database file, or use iTunes and copy the file back to a Windows/Mac OS computer, and have them host the database file. Then, other users, including FileMaker Go, can access the hosted file.
I don't know what your particular setup is but perhaps if I explain mine it might point you in the right direction.
Our ADSL router has a fixed IP address assigned by our ISP.
We use NAT port forwarding to send requests on port 5003 to the internal IP address of the Mac running FMP12.
Filemaker Network must configured and be running on the internal machine and the relevant filemaker file open.
The simply create a new host in FMGo with the fixed IP address your ISP gave you with the ADSL Router.
Things should connect up for you providing you have access rights to the file on the filemaker network.
Filemaker Pro most have the files open and marked for sharing. And when you do this you will see the ip address(es) you can connect to that database.
Open File:Sharing... and select the first option for Filemaker db. If there are no files shown in the list you will need to close sharing and open the files you want to share. In that dialog select all of the files and then on the right the method of sharing.
Note the ip address listed as these will be entered in your IOS devices Browse: New connection where you tell it the ip address.
We assume of course the WiFi you are using will be able to connect. Sometimes you can connect directly with the computer while at other times they both need to use the same WiFi router.
Now when ever you need to connect you simply tap that particular new button for this connection and the open files will appear in a list.