Part of what got me through the darkest days after Millie died was the hope that I could have another baby in the future. NOT, like you said, that she could be replaced, but because the experience of being a mother- even for 25 days- was so profound that I can't not hope to be able to do it again for the rest of my life. Have you looked into supplements that might improve egg quality? I've read some good things about l-arginine and coq10 (actually, for fertility AND PE), Though of course there's no magic bullet and you should talk with your doc about any supplements.
I don't have experience with private adoption, but I've heard it can take a lot of time and money. I do know a lot about "public" adoption (i.e. from the state) so if ever want to know more about that both the good and the bad, I have the info for you.
Good luck with whatever route you choose. I think everyone who wants to be a mom should be.
Mama to Millie
born June 2010 @ 24 wks. gestation due to my severe PE and CHF
lived 25 days, loved and missed