According to wikipedia, sodium carbonate is used to control the pH of pool water, so if I was looking for some, I'd look in a pool supply store. But mebecker is absolutely right about your solvents. You'll have a hard time obtaining them unless you work in a lab and unless you work in a lab(or have a laboratory fume hood in your garage) you do NOT want to be working with them as they are pretty dangerous. I don't know about the specific procedure that you're working with, but perhaps it would be possible to use an alcohol or oil instead?