Help with homebuying costs?

Hello! My husband and I are in the early stages of researching adoption. Through the online listing of foster children eligible for adoption, I found a sibling group of four, and they have been my inspiration for pursuing adoption through foster care. I know there's no guarantee that we'll end up with that sibling group, but the image of them is driving me to continue the process. The only reason we're not ready to adopt yet is that we don't have spare bedrooms. We have a steady income now and are slowly saving, but we want to have saved a lot more before buying, so we can have money for repairs left over after the downpayment. I was looking into homebuying grants in my area, and most of them have a lower income cut-off for a family of two, as compared to a larger family. We can't adopt (or foster) until we live in a bigger place, but we can't qualify for most of the grants until we've adopted (thereby expanding our family size). It's a vicious cycle! Any ideas on where else to look for homebuying grants, or lower-cost homebuying programs? How did you all fund your first home before adopting or fostering? Is there any grant specifically for families needing to expand their housing in order to welcome adopted children? Thanks in advance! (Current living situation is staying rent-free on my parents' property--we pay utilities and do all their landscaping. Not paying rent is what's allowing us to save faster.)