Hello dizzydaly!
These questions have been asked in the past. You can find a lot of this information in the Official Rogue FAQ.
Here is the post on upgrading the rearview mirror:
zerothread/307929
Re: Adding outside temperature display
It is not possible to add the outside temperature display... at least not easily. Basically you would have to change out the entire gauge cluster and add a sensor. It would be very expensive (in the hundreds of dollars) and would have to be done by the dealer to avoid odometer tampering.
Your best option is to add an after market temperature/thermometer. You can also get the Gentex mirror with auto-dimming, compass and outside temperature display for about $250 USD. There are photos of this mirror in the post I linked above. Read more here:
http://www.mitocorp.com/auto-dimming-mirrors.html