Refreshing private key

[Robert J. Hansen]

 > My current key is 2048 bits in length and I would like to have
 > something that is closer to 8192 bits in length. Is there a way that
 > I can accomplish this...

Definitely not from GnuPG, and probably not from without it, either.

GnuPG is capped at 4096 bits (for good reasons).

Further, you cannot change the length of the primary subkey on a
certificate.