Big rule in anything computer... don't stop installs/uninstalls while in progress. If you had let it finish, you'd lose all personal information, but you'd still have a bootable disk.
117 mb is what you're supposed to have on the first partition that windows sees.
There's no way to regain what you lost. I suspect your best bet would be to copy cm7.1 stable to your card, boot off of the sdcard while holding down the "n" button, boot into the sdcard recovery and:
mounts and storage menu: format data, format cache
advanced menu: clear Dalvik cache
Please confirm ^^ this ^^ from someone familiar with sdcard installs before proceeding tho.
If it doesn't want to come up after 5-6 minutes, you'll need to reflash your rom. You'll want advice from someone more knowledgeable with sdcard installs before doing that if there's info on your sdcard that you need to keep. It might be as easy as reflashing the rom from recovery, but I don't want to jeopardize your stock rom installation.
Sorry, I've never done a sdcard install since I have no need for the stock rom or books and no longer own a NC.