Don't be afraid to ask. If you are in need, do let your local Pastor know. They are very good about asking the Congregation for items for folks that prefer to remain anonymous.
Clothes and baby items are abundant at Garage sales. While I wouldn't suggest you head out to them yourself at this stage, ask a friend or relative if they would keep an eye out for you. There are folks (like my husband) that routinely go to garage sales in search of specific items. He skips many garage sales because he can tell just driving by it's all baby stuff.
As far as clothing - people are more than willing to pass along things and are happy to give them new homes. Be careful as you will be swimming in extra clothes for your little one. My neighbor has 7 children and she pretty much only buys shoes for the kids because so many people give her clothes.