[Indemaijinj]

For learning spells there's an east and relatively inexpensive way of increasing you intelligence:

Potions of Genius. Sold nearly everywhere these potions provide a rather hefty temporary intelligence increase. It should easily boost all wizard/bard character's intelligence to 18+

It is right that intelligence below 18 poses a limit on spells you can have in your spell book. But this limit is only checked for in the actual situation of learning the spell. The spells will not erase themselves when you intelligence drops back to normal again.

So, just collect all the spell scrolls you want to copy. Swig a Potion of Genius and then sit in a corner and write!