Well no-one else has jumped in, so here goes.
Bare in mind that there are a couple of schools of thought about water chemistry. I belong to the fairly relaxed one, make sure you get rid of any Chlorine (Cl), have enough Calcium (Ca minimum 50-100), get the pH optimised, balance Chloride and Sulphate to taste.
The other school of thought gets down to the nitty gritty of every ion - personally I think you can go way too far. Better to spend more time on stuff that matters and you will make better beer.
Your right that's pretty nasty water, looks like a really high carbonate and a fair wack of Salt (NaCl- common table salt) probably the best use for it would be Stout or other very dark beer. To be able to make most other styles you are going to need much softer water - but I suspect you have got that far.
Boxed water can get expensive, it looks like you would need to dilute your tap water about 1:3 (minimum) with pure water to get down to useful mineral concentrations.
A couple of options come to mind -
Get a Reverse Osmoses unit, they aren't all that expensive these days, strip your tap water back to near zero and build it back up to what you want.
Have a look for a local water supplier, with tap water that salty there is going to be someone supplying filtered/treated water on an industrial basis. Visit them with a couple of cubes in hand and try to do a deal. Could be a lot cheaper than buying water from the supermarket.
In most places you could think of using tank water but in Allice, supply might be a bit problematic, last time I was there spit dried before it hit the ground.
A reliable pure water supply, a decent pH meter, some food grade acid and a few basic water salts and you would be away.
Mark
