Need FAST help pls :)

Hello guys. I want to ask you a few questions. I need help by pro ppl :)
Ok here we go:I am lv 25, i have 2 champs Nocturne for jungle and top and kassadin for mid, and i have 4600 IP left. I want 1 more champ gragas katarina haimer karthus swain malza jarvan one of those. The question is should i buy 1 of those champ OR should i play with nocturne and kassadin and buy runes? If yes could you tell me i have 2 pages which runes i have to buy for them?
And is it possible to buy RPs from mobile phones?
Thanks! :)

Why u say by pro ppl???

Buy runes with that 4600 IP

Make 1 ap rune site and 1 ad rune site

but i dont know which runes :)

i would do that too but idk which runes too :P

You should defenetly buy runes first.
Go with
9x flat ad marks
9x magic resist or magicresist/lvl Glyphs
9x flat amor seals
and 3x flat ad seals
for nocturne

You can play nearly every jungle/solotop champ or ad carry with those.

for ap runes you have a little bit more of variability
you will surely need 9x magic pen marks but all the other are situational

for glyphs eg you can take flat magicresist or ap/lvl
for seals you can use flat manaregen or manaregen/lvl

for quints you can use either flat ap or movementspeed

i have 8 tier 3 rune Greater Mark of strenght for each page 8 of them, x5 resillience x4 seal of strenght