When to visit new mom and baby?

I just moved across the country and don't have any new friends my age yet. I met a girl in my birthing class who lives in my neighborhood but I only saw her the one time. She had her baby about 3 weeks ago and I'm still due in about a month. I want to go visit her and meet her new baby and bring some food (trying to make a new friend here!) but what is an appropriate time to invite myself over? A month? More? Id be bringing my husband too.