Co-Owner Traded in Our Car Without My Knowledge

My question involves a consumer law issue in the State of: Missouri

In February of 2012, I agreed to co-sign so my daughter could purchase a new vehicle in Missouri. I signed as the Primary
on the title, she is co-buyer. My daughter has struggled to make her payments and missed quite a few. Now, she shocked
me last night by calling to say she got a new car. The dealership told her I didn't need to sign the title over and
that her name would be on the new loan. I'm a little nervous, I don't see how this is possible. Is this legal? Is it possible
that I will be responsible for the new loan contract without even signing anything on the new car being that the first
loan is not even close to being paid off? She owed about $13,000.00 on her traded in vehicle and the new vehicle cost her about
$20 grand. Also, is there anyway she can go back to the dealership today and tell them that she would like to return the vehicle she
purchased last night and get her original car back? Isn't there some type of law allowing you to return a vehicle in
a certain period of time (buyers remorse?) without repercussions? Is it possible that I'm still responsible for her new loan since the other loan isn't paid off?
If so, I'm worried she'll do this over and over and I'll never be free and clear of her radical spending. Nervous & frustrated father of 8, please help. Thanks!

Was this vehicle titled in both names with an "and/or"?

I suspect this is the case and your daughter legally traded it. The dealer should pay off the 13k loan and you should not be accountable for anything on the new loan.

Give it a good 30 days and then call the 13k lienholder to be sure payoff was received or call prior to when the next monthly payment would have been made.