The Apocalypse is a ship whose tank is its range. You can fit an OK armour tank to it but you should aim to optimise its range in both DPS and tank. The fit below is around 250m and you can adapt from there. You get some pretty gnarly range on it with the dual tracking computers and you can keep decent range with it if you have any nav skills at all.
[Apocalypse, Apocalypse -Mission fit]
Large Armor Repairer II
EM Armor Hardener II
Thermal Armor Hardener II
Multispectrum Coating II
Heat Sink II
Heat Sink II
Heat Sink II
100MN Afterburner II
Cap Recharger II
Tracking Computer II, Optimal Range Script
Tracking Computer II, Optimal Range Script
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Large Energy Discharge Elutriation II
Large Energy Discharge Elutriation II
Large Capacitor Control Circuit I
Hammerhead II x5
Hobgoblin II x5
For around the value of your current fit though you can get a superior tank, more staying power, and a faster ship with the navy apocalypse.
[Apocalypse Navy Issue, Napoc -Mission fit]
Imperial Navy Large Armor Repairer
Reactive Armor Hardener
Thermal Armor Hardener II
EM Armor Hardener II
Heat Sink II
Heat Sink II
Heat Sink II
Capacitor Power Relay II
100MN Afterburner II
Cap Recharger II
Tracking Computer II, Optimal Range Script
Tracking Computer II, Optimal Range Script
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Mega Pulse Laser II, Imperial Navy Multifrequency L
Large Energy Discharge Elutriation II
Large Capacitor Control Circuit I
Large Auxiliary Nano Pump I
Hammerhead II x5
Hobgoblin II x5
Again, add value to the modules on these fits as you see fit. Personally I would suggest focusing on DPS with imp navy heat sinks before you start throwing an expensive tank on. With better tanking modules you wont need as many, so can maximise DPS which is what gets the mission done.