Credit repair situation.?

Alll medical bills from heart attack, one voluntary repo on a lemon car. Regained health and now trying to repair my credit score. Hired an attorney that specializes in that. I thought he was gong to offer settlements with the smaller debts first, as that would seemingly raise my score quicker as the creditors remove those negatives. The attorney caled me yesterday and said he got a great offer on one of the medical bills that was for $10,000 settled for $3500. The problem is I just got back to work and do not have any money saved to pay that. They also want it in a week. The question is should I stick to the plan and get the smaller ones paid/removed, sell some possessions to pay the big one, use $300 that I do have and get a securededicated credit card thru my bank and but small purchases and immediately pay them off? Which is the quichest way to get my credit score higher. One of my biggest hopes is to have better credit in order to get a newer more reliable vehicle. It would seem best to get a settlement and pay the bad car debt to get that one removed first. Car dealers/banks I feel care less about medical debt, than seeing a car loan not paid. Am I correct in that assumption? Lastly, it's not very healthy for my heart but I'm really trying to get this all done faster by working 90-100 hours a week with 3 jobs. Thanks to anybody in advance for answering my question.