[Hampshire] Upgrading Ubuntu 6.06 to 7.10

After sticking with Ubuntu 6.06 Dapper for various reasons, I now want to
upgrade to 7.10 . I have the CD and expected to find an easy way to upgrade,
perhaps with a desktop icon, perhaps in Synaptic, or even using apt-get, but
to no avail.

It seems that I have to upgrade to the next release in sequence, which is
kind of difficult for me as I don't have the CDs, and I can't find any place
on the Ubuntu site to download them from. It seems my only option is to
re-install afresh. So I'm seeking advice now. Is my understanding correct?
And what approach is best recommended?

Thanks

Kelvin