Step 1 is to test it and see where you are so that you can understand what your problems are. Then you can start to think about calling people and asking about systems.
Try Optipure. You'll probably find that the replacement cost on filters will be more than buying an RO system with a blend back to have control over your TDS and cut down on maintenance or replacement of your espresso machine.
We use bestmax premium which have sediment, carbon and softening in one filter, and an adjustable mixing valve on the head, just turn it to get the hardness (softness) your equipment needs (80ppm for espresso, 150 ppm for brewing). You don't even have to turn the water off to change the cartridge. Choose the size so that it will last a year (there is a chart), then you will know when to test or replace it next. Simple and good.
Brady is right on with testing first. We use Everpure filtration and have happy with them. Everpure's Claris system allows for custom filtration. Everpure will also send out free water test kits.