Regarding the Traffic Question, Please phone GSA - Garmin South Africa, They will help you.
Your 3590 Should have Free Map Upgrades until March 2013 - When they become available you will be able to download them From MyDashboard.
Lane Assist is built in to the City Navigator MAP, you dont need any files for the 1490.
Junction View you need the File D3529040A.JCV
You can get it from Bam-Bam post [Only registered and activated users can see links. ]

Here is the Direct link [Only registered and activated users can see links. ]