You will need to OCR it.
If you do this sort of stuff a lot, it might be worth it to invest in
ABBYY Finereader, which is supposed to be the best OCR software available.
If it is a one-time thing, you may want to just settle for
Tesseract, the best open-source OCR.
Our resident OCR expert here on MobileRead, @Tex2002ans, would heartily recommend the investment in purchasing Finereader.