Can’t recover Deleted Important File

I used a Recovery Genius program which is a utility included when I bought a motherboard. Now these utility ready brought a very BIG problem. I issue a Data Overflow error and when I opened again my Windows 98 PC. My important file were all LOST! I downloaded a demo utility named R-Undelete, this utility is good because it sees the deleted file, but the problem in the Demo version is, the file that can be recovered is only up to 64Kb, the capacity of the file I want to recover is 3.xx.

Can anybody here help me about this? If you have a registered version of R-Undelete and you can facilitate/send me a copy, a really appreciate that kind of idea, or either any other way to recover my files.

Thank you very much..