How can I get a mortgage with a 592 credit score?

My husband and I recently were approved for a mortgage and were buying a home(short-sale). It ended up taking over 100 days and we walked away from the property. We have had to start all over and now we have to have a credit score of 620 instead of 580. We have nothing on our credit except for a credit card of 500.00 it had a balance but we just paid it off. There is nothing else on our credit report that would affect us in a negative way. How long will it take for our score to go up since the cc was paid off. And are there any lenders dealing with lack of credit, rather than bad credit? Our card has never been late and all our bills are paid on time.
Oh, my husband pay child support always current, comes out of his pay check before taxes. Does that affect the debt to income ratio?

Will boyfriend's bad credit ruin our mortgage pre-approval?

My boyfriend and I are going to get pre-approved to buy a house. Due to stupidity years ago when he first received credit cards, his credit score is poor. He also just got a new job..started training this week, so his paychecks won’t even show regular pay for a while now. I’ve got a score in the 700s…have had my job for almost 2 years with consistent income. We don’t know if it’s best for me to apply for the mortgage on my own. I also have great debt-to-income ratio. Will his new job (inability to show consistent income) plus poor credit affect us in a negative way for our pre-approval or will just his additional income help us? We make the same amount of money but I fear that my income alone will look like I can’t even afford a house (if that matters), when in reality, we’d be splitting the mortgage.
Although it doesn’t matter…. a marriage IS in our future. We want to buy simply because now is a great time and we’ll end up paying less in a mortgage payment than we currently are in rent right now.

Can I get a mortgage with bad credit with the following circumstances.?

Here are my circumstances:

Transunion: 567, Esperian: 537, Equifax: 582

Annual income before taxes: 39,000, I have worked for a year

I own a home: 9 a month taxes included
I have had 8- 30 day late payments in 2 years

I have no other debt monthly, making my debt to income ratio 85/15 (I’m pretty sure)

I paid off my car, no late payments last two years.

I paid off my Providian credit card no late payments past 2 years

I have college loans in deferment until 2008, I’m currently working on my MBA

Now the bad news:

I have had 3 derogatory accounts, that I have just currently paid off, 2 were credit cards, one was a medical bill that never made it to collections I don’t think, so they haven’t been factored into my credit score yet as being settled.

I dont have any credit cards and all I pay a month is 9 on my house that I have owned for about 3-4 years.