you shouldnt be just buying a level 20, with 700 you have enough to buy roughly 80 ee weapons all the way to 55 (maximum) and a few armours and charms. to clarify i mean lvl 20,25,35,45,55 (it's reasonably normal to go in 10 level incrememnts)
i would suggest buying 90ee wep, this will cost anywhere between 100-200 fg.
I'll look into your gear and suggest some deals for you as using it all on one item is not recommended!