Would appreciate some info for a newbie

Hello all, I'm new to the boards. I've been with my husband for almost 4 years and we have a 2 year old daughter together. Unfortunately I can't have any more biological children but have been looking into adoption to complete our family and am excited but still pretty clueless about the process. lol I was wondering earlier about the whole foster to adopt scenario, especially since DH has mentioned an interest. I always thought when you took in foster children, you never knew if they were going back to their birth families so it made it harder to adopt them. Can you take in a child specifically to adopt them? I have so many questions, especially since we're getting more open to a slightly older child, probably through the toddler years. Any info is appreciated. I was also wondering if anyone has had experience with Building Arizona Families. I've talked with them to see if we liked them and they seem great, but I know it's always worth checking up elsewhere. :) Thanks for any info!