Extend RAID 5 to use unused space and add additional disks?

I am new to RAID. I want to extend an existing RAID 5.

The current setup is as follows:

Array A
unused space : 349956 MB


logical drive :1
total size 273GB
raid5
disk : /dev/cciss/c0d0

physical 
1I:1:5 - 146gb
2I:1:1 - 146gb
2I:1:2 - 146gb
2I:1:3 - 146gb
2I:1:4 - 146gb

I also have 2 more unassigned disks if it helps.
1I:1:6
1I:1:7

I want to use unused space. How can I extend the array using unused space or should I create new array of unused space?

If I want to use my unused drives too, how I can extend the existing array to include them? I dont want to lose any data, because this server is in production.

Updates-

hardware - Hp ProLiant DL380 G5 total 7 HDD of 146GB OS - Centos 5

I have installed the "hpacucli" command.

All help appreciated.

Thanks.

This is an HP ProLiant with an 8-bay cage. You haven't provided enough decent information, though.

In general, you have a choice as to whether to expand your array with unassigned disks and either increase your RAID 5 to consume the unused space OR create a new logical drive within that unused space. The new logical drive does not have to be RAID 5. It can be RAID 0, 1+0, 5 or 6... The amount of available space will vary based on that choice. The data will be redistributed amongst the physical disks comprising the array.

The HP Smart Array reference guide has a a chapter on array expansion and other operations. Read through and decide what you want.

Edit:

You will need a combination of hpacucli commands on your Smart Array P400 controller. The easier/safer approach is to do this offline and graphically using the bootable SmartStart CD. It can also be done online if you have the full HP Management Agents installed, but the path of least resistance is to use the bootable CD.

Also, if you don't need the space, you could convert this array to RAID 1+0 in the process. But that's another discussion.