Here's the deal. I'm going to tell you the truth, because I do this for a living.
582 isn't a good score. That doens't mean it can't get better, but you're going to have a hard time getting approved for things, and if you do, expect to pay insane interest.
Also, to add insult to injury, the credit score you see on freecreditreport.com is NOT your FICO score. These scores are nicknamed FAKO because the score is taken from the credit bureaus interpretation of the Fair Issac's scoring system, and these can vary up to +/- 10 points either way. In order to get your true FICO score that's closer to what lenders want to see, you have to go the myFICO website for that. Now, if you're wanting to monitor your credit, freecreditreport.com isn't bad, but there are some others out there like Truecredit.com that gives you access to all 3 reports for $14.95/month, which is a better value for unlimited access to all 3 reports.