Open Question: What is the best way to repair my credit and fast?

When I was younger I got 5 credit cards and didnt understand that I didnt actually have the money I was spending. I have paid off most of the cards except my sears account. I only used $1000 but my current balance is $2795 and I dont really have this type of money to pay them one shot. I work part-time and with the recession job hunting isnt going so well. I received a letter from a lawyer who works on their behalf and says I must pay right away. What can I do and what are my options? I made a big mistake and now Im really stuck with bad credit. Any advice....I have a secured creditcard to try and re-build credit but my sears is still in the way.....If I pay them off in payments will my credit start getting better withing a year or how does it work.....