Hi. I just got enough for Nunu and i really enjoy using him. I don't want to jungle with him, so please don't say that i need to use a jungling build. So far, my skill build is :

1)Ice Blast
2)Consume
3)Blood Boil
4)Consume
5)Ice Blast
6)Absolute Zero
7)Ice Blast
8)Ice Blast
9)Consume
10)Consume
11)Absolute Zero
12)Consume
13)Ice Blast
14)Blood Boil
15)Blood Boil
16)Absolute Zero
17)Blood Boil
18)Blood Boil

And my item build is:

(Start with Boots of Speed, 2 HP pots, 1 Mana pot)

Core items are:
1)Mercury Threads
2)Frozen Mallet
3)Stinger
4)Lich Bane
5)Leviathan
6)Morello's Evil Tome

Gold needed = 12,285

Please tell me what i need to modify in the build to make it effective in (with lack of a betr word) r@ping enemy champions. lol.

Please constructive criticism only. Ty.