Change gtext materials to bitmap

Hi guys, i have a scene used for a game, where all the materials are gmaterials and textures are gtex. Now i need the materials/textures to be standard/bitmaps. I managed to convert the 200 materials to standard but the textures remain gtex. I need to export this to fbx and the textures must be bitmaps. Does anyone know if any script can do it? Thanks.