Faye01us - I am so sorry you have problems with your apartment.
1) First thing, you are familiar with your credit score and note it is 603, that is not a terrible score. To answer one of your questions: "I don't know how long it takes between making payments and how long it takes to reflect on your credit report". Once you pay things it could take up to 3 months to reflect on your score. It is usually 30 days but it depends on how often the company you are paying reports and we live in a very small rural area. If you haven't talked to a local lender I would go to Storm Lake and talk to the bankers at NorthWest Bank, Central Bank, Security, or Meta Bank face to face.
2) Second, have you put your problems/concerns in writing to your landlord (send it certified and return reciept so you know they got it). In the letter, nicely request repairs to be completed within a reasonable time frame. Try to work with your landlord, it will usually resolve the issues if they get something in writing.
3) If your landlord is unresponsive to your needed repairs and if your apartment is located in the city limits of Alta Iowa contact the city code officer Tom Konradi and ask if he will come through the property. If you need some help call me, I have worked with other landlords and tenants to get problems resolved.
I hope this info helps, please call me 712-291-0118 or come by my office at 607 Lake Ave in Storm Lake if you would like more help.