Alfa 166 In-car Phone & Aussie Satnav

[Black Knight]

Hi Guys!
!st query:
I've been looking high and low for answers on if the in-built phone in our 166 is in fact a 2G phone that no longer can be used due to lack of support from  our telecom companies here in Oz. It was working just fine for several years...but not anymore. I read somewhere the phone used 900MHz which would make it a 3G phone which is still being supported.

My 2nd query:
Would it be possible to swap the UK satnav unit in my boot for a unit that uses Oz navigation discs...perhaps with a patch harness?

Look forward to some expert advice...thanks.
Black Knight