First of all, HAPPY BIRTHDAY to your little one!!!
Secondly, I have this shirt for Stedman:
http://cgi.ebay.com/Pet-Dog-Im-the-B...QQcmdZViewItem
It is so cute!
I got mine at a local Feed Store here in town, but I found one on eBay for ya
I don't know what size you will be needing, but I'm pretty sure that same seller has different sizes available (XS-L)