What do we need to do to make a Yamaha cvp 401 work as a church organ?

G'day,

At our church, a fairly new CVP 401 was purchased as the main keyboard instrument by a committee dominated by the occasional pianist. The church organist was away on holidays. It was a good price.
Now the organist is back and has spent some time playing with the instrument but has noted the following:
- To get enough volume when used as an organ you have to have the volume dial set to almost its maximum. This seems to be stressing both the instrument and the organist. Would an external sound system be recommended?
- related, the sound pattern is not obvious - seems to go straight down. Can it be projected away from the player as with a "normal" organ?
- presumes she will need the accessory foot volume control to get volume variation while playing?
- are the inbuilt organ flute voices sufficient or would knowledgeable folk recommend downloading other/extras? The aim at first is to set up a solid "church organ" sound before working on others.
Is there anything else she should know/do to get the best out of this purchase? I guess most folk on this forum come from the pianist side but any help here would be appreciated.