I just want to encourage you on staying home with your son if at all possible. Getting a job for when you know your husband would be home with the baby would be okay too.
You'd be surprised how much money you can save if you don't eat out, and pinch and save here and there.
My son had to go to a babysitter's house the first four years of his life.
I was miserable about it. When I finally got to quit my job and stay home was the happiest I've ever been in my life. I was able to stay home with my next two kids the entire time. NOTHING can replace those years when your child needs you most.
I'm a very strong supporter for staying home with your kids if it is at all possible. Sometimes it isn't, and it is really sad when that is the case. Good luck to you!