My cat was diagnosed with small, likely passable bladder stones. What should I feed her?

She got a steroid shot, an antibiotic shot, as well as sent home gabapentin and a urinary supplement they said would likely be needed forever. We were also told to consider a script urinary health food or an OTC as a cheaper option. We have been feeding her Nulo Medal Series grain free dry and the 3oz cans of Nulo wet food thinking it was high quality but issues still occured. Any recomendations on a OTC urinary health cat food? Wet and dry. TIA