Where can I get the higher level apparatises? for alchemy?

Are you a playing a thief character? Try robbing the local Mages guild.

Or read this:

http://www.uesp.net/wiki/Oblivion:Alchemy#Obtaining_Apparatus

I see echo cave is a good place to try for them. But no, Im not a thief character, very opposite in fact. lol Do you know if Rockmilk Cave is another good place to try for some?

Venders don't sell the top level gear of course, so random loot in necromancer and conjurer dungeons is the best bet. The master gear won't spawn until you are level 17.

You can pick a small such dungeon and 'farm it' by saving, racing to the boss chest and checking. Reload if not happy & repeat.

My fave dungeon for this (because it is so easy to race to the boss chest is named in the spoiler tag below:


Edit: Oops. I just checked Murandus' link. It's a good one with great advice too!