Hi,
first of all, you dont need to kill the yain garuga to get to rank 4*.
The best weapon and armour i suggest, is:
Great sword:try the bone katana dragon, or any GS with water attribute
SnS:Frost edge( i dont think you killed the white monoblos yet,so i will give another one)Odyssey,Sandman finsword ( all the weapons are hard to get (for you
)so better not try SnS)
Lance:Babel spear, Barbaroi tusk(mayby orgre if possible)and aqua spear+
Hammer:kut-ku chin,dynamic hammer,kutku jaw etc
Gun:dont try it, you will waste your time
hope i helped