Welcome to our forum.
Try introducing your girlfriend (and close friend) to http://www.morethantwo.com/polyamory.html
... It may answer some of their questions, calm some of their initial fears, and make polyamory seem a little less scary and alien.
Also on this site try: http://www.polyamory.com/forum/forumdisplay.php?f=26
... which may give you some more helpful intro info.
Your ultimate dream of having both of these women in a family with you is a good dream; just don't become so attached to it that it will break you apart if it doesn't come to pass. Some people are just not cut out for polyamory (even if they can accept it in others).
Hopefully people can help you here in this website.