Converting NES to GBA

Anyway, I wanted to see what Final Fantasy would look like with a bigger pallette (like add some shadings to the graphics, or fix the pallete limitations like the thief's light blue hair). And do not say anything about the playstation/dawn of souls version, they completely edited the character graphics and look nothing nothing alike to each other. So I found PocketNES, converted it, problem is, the graphics are all mixed up in the PocktNES conversion, do you know any NES->GBA(or any higher system like SNES, GBC) that would not smurf up where the graphics are?