Credit Score Management

My credit score hasn’t changed since 6/4 is that common ?
My credit karma score has been 769 the entire time. Granted, I haven’t questioned for or done much of anything that would change it.
A few months ago I tried overpaying on my credit cards so that they wouldn’t show a balance at the end of their periods but it didn’t change it.

I filed for bankruptcy in 2007, my current credit score is 640. How can I raise my credit score before purchasing a home?

I want to apply for an apartment but they need a 625 credit score. I lost my job for a few months and am now behind on two accounts.
My credit score is 597. I can bring the accounts current in less than three weeks but will just that be enough to raise my score those 28 points? I don’t want to waste my application fee just to get rejected.