Well the powerhead won't provide extra filtration, unless you had a sponge attached to the intake?
the XP3 is rated for tanks larger than that but it's not enough, get another can or HOB as Farrmanchu suggests.
My larger cichlid set ups:-
400 litre - Eheim Pro 2226 + Juwel Jumbo (approx 1750 lph)
350 litre - Eheim Pro II 2126 + Juwel Jumbo (approx 2000 lph)