That's quite a nice bow for a mere blue one!
Unfortunately, dreams must be shattered:
First; Fool's doesn't exist in 1.07.
Furthermore, a Grand Matron Bow (qlvl67) caps out at alvl56, and a Hydra Bow (qlvl74) caps out at alvl66. This means that Cruel can indeed spawn (alvl51), but Grandmaster's can not (alvl69).
Master's (alvl56) can spawn though, which is 250 AR and 150% ED at max.
I haven't made a "proper" list of affixes myself, so dunno what you would want in stead of Fool's. The affix excel files are a bit of a mess, and a hassle to go through.
+% Damage to Demons would most likely be the best stat, had it not been bugged to not work with arrows.

According to the patch notes, this wasn't fixed until 1.09.
Don't forget that crafts will not generate more than 4 affixes, so you might actually want exactly those: Master's, Cruel, of Evisceration and of Alacrity.
A couple of nice GMBs have been posted in this thread, but since some were posted in the form of a picture rather than a read-out, you might not find all of them with a search.
Lastly, just fyi; clvl
does not matter for the qlvl of the reward that you get from Anya. So if you'd want to farm them, or obtain at least 1 GMB, you do not have to bother leveling the rushee(s).
I personally have received a Hydra Bow at clvl 1!
(Weirdly enough, even while ilvl = clvl (the mentioned Hydra Bow was ilvl 1), the affixes were at least alvl30, and possibly higher (didn't really check). I doubt affix generation for these items are identical to crafting, but who knows. Not that it matters if you plan on crafting, of course

)
Edit:
Btw, I'm under the impression that a GMB is an objectively better pick than a Hydra Bow: GMB has more min and more max damage, while speed, requirements and dexterity_bonus are identical.
There are probably a few extra affixes that a Hydra Bow can generate, but I doubt they are affixes you want, which would mean the GMB has more chance of generating the affixes that you do want.