How do you get the Wizard Tower in the elders scrolls 4 - Oblivion

To get the Wizard Tower you need the Wizard's Tower DLC for the game, you can acquire this online as part of an additional content pack. I acquired it through the latter method wil the Knights of the Nine DLC collection pack, which also came with numerous other content packs such as the title pack, Vile Lair, Thieves' Den, Mehrunes' Razor, Horse Armour, Spell Tomes and The Orrery.