I'm a realtor in here in Wethersfield. You have got some excellent responses to your question. If you would like to come by my office, we can discuss what it would take to get you pre qualified.
I understood you question is how much of a down payment is needed if you don't have good credit. The number one thing a lender will be looking for is income to repay the loan. Credit is an important factor and you will need any past due items to be paid in full. It will not likely be possible to obtain a loan if you still have outstanding past due debts. You will probably also be asked to write a letter explaining what happened. Having a high down payment - even a really high one like 30% or more - will not be enough for most lenders to ignore income and credit factors.
Start by pulling the free credit report to see what is past due and correct any errors.
SSG Real Estate
Best of Luck!
CG Real Estate