The HPLIP site says you need hplip 2.8.10 or higher.
hplip 3.9.12 is available in the MEPIS 8.0 Community Repository.
Under Settings -> Repositories
in Synaptic, add this entry:
Reload, and you will find hplip 3.9.12 listed. Debian splits hplip up into several packages so you might also wish to install hpijs, hpijs-ppds hplip-cups & hplip-gui just to make sure you have everything.