Could you call your old doctor's office to find out if they have the last record of your insulin:carb ratio? I don't know if that is a default value for the Minimed 722 or perhaps a value that you saved previously. I use insulin:carb ratios anywhere from 1:4 to 1:10 depending on the time of day.
I don't use a Minimed pump now but I'm sure there are many on this site that do, perhaps they could help with that part of your problem.
I know that Minimed (as well as all the pump companies) only says to use cartridges once and then toss. If I were in your situation I would use them at least twice. As for the infusion sets, you can only use them once. You could extend the life of the infusion sets by using a syringe for your boluses and push the infusion set to beyond three or four days.
Last year when I changed from a Minimed pump to an Animas pump, I was left with a large supply of Minimed infusion sets and cartridges. I ended up giving them all away to a diabetic that was mentioned in a USA Today story about the pressing national need for real health care reform. She was in much the same situation as you, an insulin dependent diabetic on a pump without insurance coverage. Her grateful email that she sent me when she received all my excess supplies was more than enough payment for me.
I'm hoping that someone on this site may be situated much as I was one year ago and can find it in their heart to pay it forward!