Hi,
The following is the simple way to do it, although not as neat as having a built in unit.
There are numerous aftermarket attachments for you to choose from. Just 'Google' aftermarket fingerprint scanner.
Here is but one example. It is not meant as a recommendation for the particular product.
http://www.amazon.com/Security-Biometric-Fingerprint-Reader-Password/dp/B006FTPQOK/ref=cm_cr_dp_asin_lnk.
It attaches to the laptop via a USB cable and comes with its' own software.