Memory stick problem

Hello,

I have a Lexar 4gb firefly memory stick. This morning it was working perfectly well, but after saving my last info in it, it is completely full. Instead of allowing me to extract the files from the memory stick it now tells me to format it which is going to be a cause for loosing all my info which I cannot afford. Anyways I ended out formatting it out of frustration but am looking for a way in which I can recover the lost data and store it on my c-drive. Can anyone please help me with this. I do not have enough money now to pay for software and hope and pray that there is another way to get my information back.