ECC encryption in practice
The programming aspect of this question should be asked on StackOverflow, but I suppose you can figure it out all on your own. 

Yes, you need to generate ECC keypair if you want to use ECC algorithms. Every type of public-key cryptography suite require specifying algorithms, if your PGP keys are already using ECC algorithms (ECDH, ECIES, ECDSA), then you may reuse those depending on software support as not all libraries and apps support all formats (there are SSH, PKCS-PEM, PGP formats from what I know). 

Also note that you should generate different keys for different purpose - don't reuse encryption key for digital signature and vice-versa.