Your situation is REALLY easy to get by and fix.
Go in and pay it off. Literally that is it. However, DO NOT make a payment plan. If you set up a payment plan, then you are hosed. Credit is reported from the time the account went delinquent. You are not here to set up a payment plan, you are here to pay it off. If they want to have you pay it off for less, you may want to avoid that as well... Then it will be a "Charge-Off - Settled" instead of a "Charge-Off - Paid." Unless they agree to list it as a "Charge-Off - Paid" for a lower amount, and get that in writing.
I am not sure you want to re-open the account either, because then that will probably (not sure here) also cause the late payments to stick around, unless they agree to remove them. Maybe you could ask them to keep the account open under the agreement to remove all late payments? Not sure how big your town is, maybe they want your business. You could even ask them to cut your limit to a lower amount until you have shown your willingness to be responsible and make payments?
Hope this helps! And get everything in writing!!!
