I din't think you can purchase just the insides of the remote. The remote control part number is 996.637.243.00 which includes part numbers 7 & 8 in the picture in the previous post by SD987.
Try this link for the part from Sunset Imports:
http://www.****************************************************.com/porscheatcost.php
Not sure about programming the new remote.
Also, try this link for a Boxster parts list:
https://techinfo.porsche.com/techinfo/pdf/en/catalogues/E_986_KATALOG.pdf
Regards,
derb