Code:
int combotype;
int i; int j; int x; int y;
for(i=0; i<256; i++){
	for(j=0; j<176; j++){
		if(Screen->ComboT[ComboAt(i,j)] == combotype){
			x = i;
			y = j;
			i = 256;
			j = 176;
		}
	}
}
That should work, but I wouldn't advise doing it too often...