I think he is looking for screws and not screw-drivers.
Try computershops or laptop repairshops. If you have a sample you can even try engineering supply shops like Bolt & Nut.
Here's the guide from iFixit.com showing the different type of screws used:
https://www.ifixit.com/Guide/MacBook+Pro+17-Inch+Unibody+Hard+Drive+Replacement/3401
DX.com have a set of screws for $3.77 : http://www.dx.com/p/replacement-repair-screws-set-for-apple-macbook-pro-13-15-17-271046#.VMIBZcYsm2w
Is dx reliable and safe?