presence area of effect problem?

is it important than minions damage or minions attack speed?
how can i increase presence area of effect?
only can be seen on scepter?

Id look into Alphas Howl helm(Double your presence). Presence will increase the radius of your Aura on your Scepter it will also increase certain skills/uniques presence.. such as gravebinds gloves.

Mainly support builds will use presence with a party.

Generally you are with your minions :). google "poe2db presence" you will find more information about it. Skill gems/passives/uniques.