My high elf atronach would rather not lose all of her health when random lightning bolts strike her. I looked around but i can't find a list of Spell merchants and their exact spells just the colleges the spells come from. Thanks in advance

If you click on a vendor's name on the right hand side of this list-

http://www.uesp.net/wiki/Oblivion:Spells

It will bring you to their individual page which lists what spells they sell.

As for spell absorption, the two guys at the Arcane University's Praxographical Center each sell one.

http://www.uesp.net/wiki/Oblivion:Agata

This is what I sort of did:

Wait until after level 15, and then run around and close Oblivion gates. Save before you grab the sigil stone. There is one sigil stone that will give you Spell Absorption 15 points. Load if you didn't get it.

Do this and get an equivalent of at least 60 Spell Absorption via sigil stones and then put them on whatever "best armor" you can acquire. I recommend waiting for Daedric or glass armor, or the Shivering Isles armors that you can get. So you can walk around with 110 Spell Absorption as an Atronach.

As for buying the individual spell I believe you can get it from Agata.

You can do the Max spell absorption, you can cast elemental shields, or you can buy hands of the atronach from the market district. Lots of work arounds for this.