Bleeding heart me wonders why you didn't teach your daughter to be responsible in the first damn place. Sorry, but it really pisses me off to hear parents complain about their kids not knowing how to do things when it was THEIR job to teach them those things. You sound as immature and selfish as your daughter.
I'm an adoptive parent and really believe adoption can be a great thing. What you need to consider is that adoption is a life long decision and it doesn't get rid of a "problem". Forcing someone to relinquish their child is wrong on a million different levels.
For all of your sake I suggest you research "theraputic foster care" for your state. Many agencies offer residential support for pregnant teens. Considering how you seem to feel about all this, it might be the best place for your daughter.