yup, cheaper solution is to buy another copy of GTA4 (NTSC).
btw, anong tv ba gamit mo? usually kasi modern TVs support PAL and NTSC - multisystem na. baka may pag asa ka pa.
another suggestion, medyo long shot, baka may kaibigan kang merong multisystem na tv and hindi HD, subukan mo dalin ps3 and gta mo, testingin mo dun.