How did I do it? Well it is explained in the instructions on the page. Nothing is required to be tweaked, changed at MiFi end. What I did is take my old LinkSys wifi router and flashed it with DD-WRT firmware.
Why did I flash my router? Because it's own firmware did not have bridge mode (you cannot however flash any router. Check dd-wrt.com for compatibility. Now many manufacturers of routers are using DD-WRT as stock firmware).
What is bridge mode? It allows two wifi routers to speak to each other. Now my Linksys takes wifi signal from Zong MiFi and redistributes them. No physical connections are required.