I think you may need to expand your options to internet/mail order to really get what you need, but it's possible to do without that convenience.
I think Petsmart still sells Flourish Comprehensive, that'd be a good trace element mix to use, they probably have fert tabs by Seachem too.
You need macro fertilizers though, Fleet enema is a perfect source of Phosphorus which you can get at the pharmacy or walmart. Greenlight or Spectracide Stump Remover is 100% KNO3, which is your Nitrogen source. I believe folks have said that salt alternatives in the grocery store like "no salt" or was it "New Salt" (something like that) are sources of Potassium Chloride.