dual cardholders

Help! I have one existing credit card debt left that is haunting me from my closed business. It is a "corporate" credit card that was in the name of my former business partner. I assumed responsibility for the debt, but I am now unable to pay it due to debilitating medical problems. I have spoken with the credit card company, and they are considering allowing me to make a "settlement" for about a third of the balance and "call it even."

My biggest question is: will this affect my former partner's credit rating, and will she learn of it (we are no longer in contact)? Or will they go after her for the balance? The account is already delinquent by two months.

The twist: as business partners, we used to sign each others names to things for years. I don't THINK this is one of the things I signed for her (the signature card), but I'm not SURE. We didn't set up a power of attorney to allow this, but had been doing it for so long with complete trust that it never came up.

Sidenote: the card was opened with mutual consent and the debt was rung up by both of us on behalf of the business.

I am in Florida, and the business was in Florida, but the partner now resides on the other side of the country.

Thanks for any advice anyone can give!