Sorry typo, 2 more credit cards.
This will bring up your score the quickest. You need some tradelines reporting some good history to rebuild and get your scores moving.
After a good 6 months I think your score will move into the upper 600s, but only with the new credit cards.
I would also recommend forgetting about trying to get approved with a 620 and waiI until you are over 640. my scores were real close to yours about 6 months ago and I was denied when I applied with a 629. From what I was told you need to be squeaky clean (no baddies) to get approved under 640 for USDA guaranteed.
Like toolman said though, you need one more CC minimum
Do I really need another card, if so does it have to be a store card like best buy, walmart, amazon or? I have a secured credit card, shouldn't it be enough?
Do you know how the score process is, like how many points for every move?
One card might be enough, there's no set rules as to how many points your gonna get per crd ect... All I can tell you is that my score went up dramatically after I (reluctantly) opened my 2nd CC. With your scores you should get approvevenly an unsecured card. This sight is chock full of excellent advice on which to get. Make sure it reports to all 3 CRA (I unknowingly chose one that didn't report to EQ). A 3rd card might/might not help so much depending on AAOC. Do some research, all the answers are here already
again I'm no expert, just sharing my exp with similar credit profile