I assume some repairs need to be done?
"If the repairs are not completed before the first of November, I shall be forced to direct my funds towards bringing the house up to a proper standard for habitation in lieu of paying the rent."
Here are a few tips for formal writing:
- keep it indirect: talk about "it" instead of "me/you". This means using passive voice quite a bit.
- give specific information, especially dates.
- no contractions.
- keep it impersonal (you were right to use "be obliged", as if it were not your own decision).