Most marine LFS will sell you RO water in a pinch. Since you're with me in the states, I'd suggest buying an RO unit off ebay. Just make sure it has a flush valve or flush kit installed . You can go with a 50 or 100GPD unit. DI cartridges are nice, but the RO membrane itself does most of the work.
As for the whitespots, the fish will show signs of ich more when it is stressed out. If its not stressed, it will show fewer spots, if its stressed, it will "break out" in spots as you're seeing. Gotta get that chemistry under control first and foremost
Edit, dont worry about the pH for now, so long as its stable. Stable and low pH is better than wildly swinging high pH
As for the whitespots, the fish will show signs of ich more when it is stressed out. If its not stressed, it will show fewer spots, if its stressed, it will "break out" in spots as you're seeing. Gotta get that chemistry under control first and foremost
Edit, dont worry about the pH for now, so long as its stable. Stable and low pH is better than wildly swinging high pH