Yes, you will want to use the e-junkie shopping cart.
What you need to do is upload the digital version of the CD to e-junkie (There are some paid plans on e-junkie that allow you to host on your own server, as well). Then, the visitor to your web site can purchase the CD and will also receive the digital version.
The thank you page will have a specific download link unique to that person who makes the purchase.
You can do this all on your existing page. Just add the e-junkie button in place of the PayPal one.
E-junkie integrates with PayPal, so your visitors will actually make the payment via PayPal just as has always been the case. They will just initially use the e-junkie shopping cart.