tsarstephen is right -- you'll need a lawyer no matter what.
Is your fiancee fully prepared to legally adopt your child? You'll have to do the homestudy, and all of the other legalities of adoption. You'd probably have to have all that in place before the state will consider terminating the biological father's rights.
Is the bio-dad paying child support? If he is you'll probably have a hard time terminating his rights.
Most attorneys will offer a free consultation. Look for an adoption attorney that has some experience with de facto parenting (although a quick google search shows that Virginia doesn't recognize this provision (at least as late as 2008 (things might have changed since then)))