Ok, so at least you have a budgetary number to compete against... 😉
Get a quote from your vendor how much it would cost to replace the "heaviest" c.u.r.s.o.r.s.
Once that's done, your I/O wont suffer that much anymore and you might be able to use the hardware as a VM host.
On the other side you should really consider a backup strategy for your server. So, a second system used as a VM host but being able to be used as a backup system for your app might be the way to go.
A UPS will protect you from a power failure. But how about hardware defects?