enlarge disk space on a Sun 4/260

[hairu chang]

Hi, I have a Sun 4/260 with xylogical 450/451 disk controller and 2 280mb
disks. Now we already use 90% of our disk space.  Our Sun sales person
told us it would cost us around $13000 to upgrade our disks, because the
controller needed be changed.  Does any one know a cheaper way to do it ?
Please also tell me the detail procedures to format and install the disk.
Thanks in advances !

Hai-Ru Chang