can anyone help me

Keep synthesizing the new items until you've got them all. Then get the ingredients necessary to synthesize the Ultima Weapon and, once you've done that, synthesize the Ultima Weapon and there you go! A brand spanking new Ultima Weapon

thanks is it as awsome as the one in kh2

No, not really but its' the best you'll get in the english version.

Agreed. The Ultima Weapon is the best weapon in Kingdom Hearts 1, however, they really downplay it in Kingdom Hearts Birth by Sleep something which really shouldn't have been done

One word : Moogle