PERC H730 - RAID 5 - Expand Existing Storage

Hello, Dell Comrades

We have a new client that has this setup:

PowerEdge T630

Windows Server 2012 R2  (I know, YUCK! We are planning on upgrading soon)
PERC H730 - RAID 5

x5 931GB SATA HDDs

We are running very low on storage space. But we need to buy some time for the client to budget the server replacement project next year. Is there anyway to increase the storage on the existing RAID 5 setup?