Topic title^
really need to know thanks!

Balgruuf's right hand man, he's fancy, pretentious and in green. check the Dragonsreach(?) near Balgruuf at the throne

be advised you need to do a few quests to even get the option of buying a house.

and.. thats the best way I can put it without being spoilerish..since you asked in the wrong area imo

Proventus Avenicci, the steward of the Jarl.

Talk to his assistant. He was standing next to him when I was there.

awesome ty guys, now where is the house I brought? :S

This I can't help with. I want a house bad but I've been using my gold for Tomes/Spells. Finally I can be the mage I wanted to be instead of using a sword.