Do I keep, or replace, the Infinity Amp and radio in a 1997 Sebring?

Vehicle:
1997 Chrysler Sebring Convertible JXI 
2.5L,V6, Gas, FI, VIN "H", EEB, JXI

I think that the Infinity Amp under the passenger seat is bad.

What's the best option?

1. Replace the radio, amp, and speakers with the latest 
and greatest?  If so, with what?  Will I need special
cable adapters? 

2. Buy a used amp & see if the radio will work?
I'm guessing that my existing radio will not power on
without the amp installed and working?

3. Buy a 3rd party replacement amp & use the existing
speakers and radio?  If so, who makes a replacement amp?
Will I need special cable adapters?

4. I have a brand new Sony radio that I could install. Will it
work with the Infinity Amp and the Infinity speakers?  I assume 
that I will need special cable adapters to connect that new Sony
radio/CD to the connectors that were plugged into the old Infinity
radio/CD box?

THANKS,
Gene