WiFi router or cable adapter suitable for old Axim X3

I have an old Axim X3 with inbuilt WiFi.

I have a Sierra 4G Wireless Mobile Broadband USB modem.

My ISP is Telstra Bigpond.

Firstly, can I connect my Axim directly to the Sierra USB modem?

Secondly, what hardware do I need to connect my Axim directly to the Sierra USB modem so that I can use it when travelling, as my wireless broadband connection is to a desktop.  The Axim is my only portable device.

I was thinking in terms of a cable adapter that will connect the Sierra USB to the sync plug so that I can log in using the Axim when I'm not near any public WiFi hotspots.