eventually you will be able to buy them from shops but they are pretty pricey if you want a few and don't have the golden gaffe DLC, i'd start saving, sometimes you can get them as drops from certain enemies but only a few offer them maybe 3 chapters at most. You are pretty close to getting one i'm sure, i never ran out of one on my first playthrough. You may want to consider reclassing panne to give her more of a skillpool though instead of keeping her taguel if she is close lvl 20, just throwing that out there.
