Personal Loan Advice

I need some advice on small personal loans. Tldr I was in an abusive relationship and there are late fees for my rent that I am now responsible for. I asked for my landlord to waive $500 of the fees in exchange for plumbing issues I had in the apartment that damaged my personal belongings. He agreed but wants me to pay the remaining $725 of late fees immediately (I asked to be able to pay $240 for the next three months but he said "Unfortunately the full payment must be made for the deal.") I am possibly needing to reapply for this apartment without my ex so I am trying to remain in this landlords good graces and am appreciative of him working with me regarding the fees. My credit is currently poor (513). I will be visiting my local credit union and trying to take out a personal loan of $500 that I will repay within two months. I was just wondering if anyone has any additional advice or experience with this kind of situation, what type of interest rate I should expect, and what my best options are if I am denied for this loan.